Use of desalinated and brackish water in agriculture in Israel

One of Israel's desalination plants produces more water than required for urban use, and half of it is funneled to agriculture. 

Field in Israel / Natalinasser / CC-BY-SA 4.0

Scientists have discovered that desalinated water's low mineral content, once believed to be an advantage, is bad for crops. Desalinated water is void of any minerals whatsoever, minerals that are critical for the growth of fruits of vegetables. Calcium shortage, for example, causes physiological defects, while magnesium shortage damages the plant's development. If the crops are grown in sand or off the ground, the damage is even worse, because the soil cannot provide the missing elements.

In turn, human beings consuming these plant products get less magnesium in their food. Magnesium is a crucial mineral, deficiency in which may lead to medical problems, including heart attacks.

The Israeli government is obligated by contract to sell, so the state prefers that farmers buy expensive desalinated water. The fact that no crops will thrive in desalinated water if its mineral content is not replenished, doesn’t always interest government officials. 

Chilika Lake, India's largest lake, classified as 
brackish waterbody / gppande / CA-BY-SA 3.0

Brackish water is water that has more salinity than fresh water, but not as much as seawater. Although Israel’s Negev Desert lacks any major freshwater sources, there are a number of underground brackish water aquifers whose water is accessible by drilling. Studies conducted at Israel have turned farming with brackish water into an essential component of agriculture in this arid region.

Direct irrigation with brackish water has been successfully pioneered for those crops that can thrive on its special qualities, for example olive tree groves. Barnea is the name of a type of olive developed by local scientists that actually loves brackish water. 

Another way brackish water can be used is by mixing a minimum of 15% of brackish water with desalinated water. Essential minerals such as sulfur, magnesium and calcium are reinstated, and the newly-created “cocktail” is perfect for growing various crops. Different crops like different combinations of brackish and sweet water – for example, just before becoming ripe for picking, cherry tomatoes like 60% brackish water and 40% fresh water. Brackish water makes the cherry tomatoes tastier, smaller and also increases the percentage of antioxidants.

Desalination is unaffordable and destructive of the environment & livelihoods

According to the International Desalination Association (IDA), there are around 18,426 desalination plants spread across 150 countries, benefitting as many as 300 million people.

55 % of Israel’s domestic water consumption is manufactured and many countries, especially in the arid regions of Northern Africa and the Middle East, find desalination a relatively cheaper option compared to other alternatives.

India’s average annual rainfall is about 1,200 mm. In contrast, middle eastern countries such as Saudi Arabia, UAE and Qatar get much less than 100 mm a year. Many developed countries in Europe and even the US, get much less rain than India (715 mm 
yearly for the latter). 

Rain at Plant / Prabas007 / CC-BY-SA 4.0

Desalination as a “solution” for Tamil Nadu’s water problem is what social activists disparagingly refer to as a ‘technofix’. Technofixes and their proponents are dangerous because they aggravate the problem that they claim to address by lulling society into a false sense of complacency. Their actions highlight dubious benefits even as it exacts a heavy price on the environment and invisible and marginalised sections of society.

A new mission on desalination is in the works in India, according to union minister of earth sciences, Harsh Vardhan. Despite the reliance on desalination, countries like Israel have invested heavily in securing their water sources and recycling used water. For example, Israel treats close to 85 percent of its wastewater which it then uses for irrigation, gardening and industrial purposes. In fact in 2005, less than seven percent of Israel’s total water needs was met through desalination plants.

Another country that is often on the cutting edge of technology and practicality is Singapore. It is working to ramp up the recycling of treated sewage as well as construct more desalination plants. The plan is to increase water supply from the former source from 30 % to 50 % and the latter from 10 % to 30 %.

Singapore River / Formulax / CC-BY-SA 2.0.

In 2002, Singapore reclaimed water from a sewage treatment plant at an additional cost of 30 cents per thousand litres using advanced membranes, filtration and disinfection. Desalinated water is more expensive by two and a half times at 78 cents per thousand litre, and Singapore is resorting to it only as it has little land to store rainwater.

With the ongoing awareness programmes, Singapore's National Water Agency aims to reduce per capita domestic water use to less than 150 ltrs by 2020. Compare that to over 400 ltrs per day use by US residents and 550 ltrs per day by UAE residents, when living standards of Singapore residents are not thought to be poorer compared to USA and UAE. So responsible planning and use need to go hand and in hand with planning for new water sources. 

Critics decry the high cost and high energy consumption of desalination, which can have a negative impact on the environment and on our oceans. Desalinating 1 cubic meter (1000 litres) of water requires 3.5 units of electricity per 1000 litres. In comparison, the average daily electricity consumption of an Indian household is about 3 units of electricity.

Kanchipuram, India / McKay Savage / CC-BY-SA 2.0

Thus, an average family of five consuming 675 ltrs for domestic use at the rate of 135 ltrs per capita (the norm suggested by the Central Public Health and Environmental Engineering Organisation for cities with piped water supply where sewerage system is existing/ contemplated) will increase its electricity usage per day by nearly 80 % (an addition of about 2.3 units of electricity) simply to use desalinated water - even if the desalinated water production cost is subsidized by the State. 

Together, the two desalination plants in Chennai are estimated to consume between 500,000 to 700,000 units of electricity each day if they run at full capacity– enough to power 2 lakh households for a day. The electricity required to run the desalination plants will come from power plants, which have their own negative impacts on the environment, climate change and human health. 

The end-user price for water manufactured at the newer, lower-cost Nemmeli desalination plant located in Chennai is about Rs 50 per 1000 litres or Rs. 34 for 675 ltrs a day for a family of five. A month's usage thus translates to more than Rs. 1000 for such a family. 

Arizona Cap Canal / US Govt.

In contrast, the average cost of production of the conventional piped supply of water is almost one fourth the cost of production in desalination plants. For example, Chennai Metrowater buys water from the Minjur desalination plant at 54 per kilolitre (Kl). On the other hand, conventional sources cost 13/Kl. Thus the water supply for an average family would cost about Rs. 9 a day or about Rs. 260 a month if the water was sourced from conventional sources. 

Even in Israel which is tom-tommed to have the most cost efficient technologies for desalination, the price of desalinated water is ILS 2.50 per cubic meter (ILS - Israeli New Shekel), while brackish water pumped up from underground acquifers, costs only ILS 1.00 per cubic meter. Israel’s Sorek plant, which is the largest in the world, can produce a thousand litres of drinking water for 58 cents which is still nearly double the cost of recycling wastewater in Singapore. 

According to the Department of Atomic Energy, Government of India, on an average, the cost of conversion of sea water into desalinated water is about 10 paise per litre of water produced. That would imply a Rs. 100 cost per 1000 ltrs of water produced !

And as to proponents of using desalinated water for agriculture - just the water costs of producing a kilo of rice using desalinated water will be about Rs 100 in Tamil Nadu.

Palm Tree Farm in Israel/ Tiia Monto / CC-BY-SA 3.0

The glowing articles in the media about the transformation of Israeli agriculture due to desalination, fail to highlight the costs and contexts within which such a transformation can be justified. Israel’s water needs are paltry compared to India's. Israeli agro-climatic conditions are vastly different. The arid regions of Israel do not receive the kind of rainfall that many regions of India get. And Israel grows vegetable and fruit crops suited to its arid lands, unlike much of India focusing on water intensive crops. 

Beyond the links to climate problems, marine biologists warn that widespread desalinisation could take a heavy toll on ocean biodiversity; as such facilities’ intake pipes essentially vacuum up and inadvertently kill, millions of plankton, fish eggs, fish larvae and other microbial organisms that constitute the base layer of the marine food chain. Marine fisheries, which are an important source of inexpensive protein and livelihood for lakhs of fishworkers, will be harmed.

Is Desalination of Sea-water in Chennai really a Success Story ?

Two 100 MLD desalination plants, one in Minjur and the other in Nemmeli, now contribute close to one-third of Chennai’s total water supply. The first of these started operating in 2010. Owned 75% by infrastructure firm IVRCL, already by 2013 the plant had run into financial trouble. IVRCL is looking to exit the project. 

Rainy day in Chennai / Aadhitharajan / CC-BY-SA 4.0

Most of the average annual rainwater of 1,200-1,300 mm that Chennai receives—more than Bangalore’s 900 mm or Delhi’s 800 mm average—flows into the sea. Leaks and pilferage are the bane of Chennai’s water distribution network. Only 65% of the water from the city’s treatment plants reach consumers while in Germany this is as high as 95%.

Is it appropriate to compare a city like Chennai which receives almost three times as much rain in a year as that of Tel Aviv, Israel ? Professor S. Janakarajan of the Madras Institute of Development Studies says : “Seawater desalination was conceived as an option for providing potable water in rain-starved countries, like those in the Middle East."

"Where is the need to go in for such an environmentally damaging and costly exercise? It should ideally be the absolute last resort, which in this case is not”, the Professor asks.

Researchers have questioned the need for the state to back desalination projects when recycling of used water can be more cost-effective and environmentally sustainable too. 

The Nemmeli plant inaugurated in February was delayed for years by political bickering and execution hurdles. The plant was to be built at a cost of Rs.1,000 crore to pump out 300 mld of treated sea water. While the cost remained at Rs.1,000 crore, the capacity was whittled down to 100 mld. Two cyclones damaged the plant during construction. 

Back in 2013, a fact-finding team looked into allegations of environment and human rights violations arising out of the construction and operation of the Nemmeli plant. The report recorded villagers’ accusations of the desalination plant eroding the coastline and endangering their livelihoods in addition to turning the groundwater salty.

Dead Sea salt / Tiia Monto / CC-BY-SA 3.0

The brine released by desalination plants settles on the surface of the ocean and disconnects oxygen causing oxygen deficiency in the ocean floor area, which threatens marine life.

There are some species of fish which feed, breed and spend most part of their early life along the coast. If the hypersaline reject is let out close to the coast, the probability of these organisms being affected is rather prominent. In addition, high-pressure motors used to draw in water also brings in marine life forms of varying sizes despite nets placed to avoid relatively larger organisms. Fish, fry and crabs get crushed and killed in the process. Loss of income and marine resources cannot be discounted as fishermen in and around Nemmeli have observed it firsthand.

In addition to wrecking local livelihoods, the plant has depleted the area’s freshwater sources. During the plant’s construction phase, groundwater was pumped out continuously to sink deep foundations. This resulted in rapid depletion of the available underground sweet water, which eventually got replaced with intruding salt water from the sea. A plant designed to produce fresh water from the sea had, in reality, abetted the conversion of the existing fresh water in the region into unpalatable salty water. Water in handpumps in the area turned saline, forcing the neighbours of this drinking water factory to rely on expensive bottled water.

Carlsbad desalination plant, California
Bovlb / CC-BY-SA 3.0

Structures built into the sea for plant construction triggered rapid sea erosion resulting in the loss of an entire line of community buildings built by the Rotary Club after the 2004 tsunami. 

Inhabitants of the Nemmeli plant's neighbouring villages allege that water let out from the plant has reduced the beach to a thin strip, forcing the sea water to come close to the land where they live.  Villagers sent various petitions to the chief minister of Tamil Nadu, their local MLA and to the Chennai Metro Water. The state government responded to complaints by jailing tens of fishermen. Fishermen were barred access to fishing grounds in the vicinity of the plant's intake pipeline.

The Environmental Assessment Committee (EAC) of the Ministry of Environment, Forest and Climate Change noted in Nov 2017 that there was already significant erosion of the shoreline due to the 100 MLD plant commissioned at Nemmeli. 

Dead Grouper Fish / Jbellegaribay
CC-BY-SA 3.0

Even in the Middle East, which dominates the desalination market, there are no proper methods to tackle the brine and reject water. A 2011 study by Pilar Palmolar, Spain, states that extinction of fish larvae has been observed near brine discharges in Ashkelon, a coastal city in the southern district of Israel.

"Our land and livelihoods have been compromised so that people in the city don’t go without water. But we don’t get a drop of drinking water from the plant,” complains Santhosh, a fisherman, whose village is near the Nemmeli plant.

Janakarajan insists that our aim should be to conserve water received during the monsoon months instead of resorting to options like desalination after letting fresh water run wastefully into the sea. “Desalination is extremely unfriendly to the environment, and contributes to coastal ecological degradation, in addition to being ridiculously expensive.”

Chennai Metrowater now proposes to construct another 150 MLD plant at the same location. The project documents falsely describe the beach space as barren land, masking the multiple uses that fisherfolk put these livelihood commons to. Villagers are concerned about pollution, loss of livelihood spaces and erosion. They are worried that erosion will bring the sea closer and expose them to danger. 

Beach FisherMen / Nagafotos / CC-BY-SA 4.0

They know from past experience that MetroWater's assurances of "negligible" impact are baseless, and that the statutory conditions imposed as part of the environmental clearance by the Ministry of Environment will not be followed. They know that the Tamil Nadu Pollution Control Board and the State Coastal Zone Management Authority will take no action in the event of violation. They know that they will be terrorised by the police if they voice their fears.

Currently, only 26 per cent of Chennai’s drinking water comes from the two desalination plants, with a total capacity of 200 MLD. To meet the city’s drinking water needs, conserving and protecting lakes and wetlands is a cheaper and environmentally better option than desalination. These wetlands will also save the city from urban floods. An analysis by CSE showed that post the year 2000, Chennai lost 50 per cent of its water bodies due to urbanisation. This resulted in seven major floods in the last 15 years. 

The Indus Valley Civilization did not flourish by the Saraswati...

Analysis of the sediments on the river bed and satellite imagery showed recently that the majority of the Indus civilizational sites were grouped around the Ghaggar-Hakra rivers which are monsoonal rivers and not perennial ones. Via checkdams and storage sites, the cities stored water for use in the non-monsoon seasons. By not being near perennial rivers, these settlements avoided the destructive floods and change of channels that the mighty rivers are capable of.

Tall well, Mohenjo Daro / Nikesh Chawla / CC-BY-SA 4.0

A recent study showed that Indus urban settlements developed along an abandoned river valley rather than an active Himalayan river. This remnant of the inactive river is a former course of the Sutlej River. The flow of the Sutlej in this course terminated considerably earlier than the Indus occupation, with diversion to its present course completed 8000 years ago. This enabled long-term stability for Indus settlements sited along the inactive river.

Alluvial landscapes built by large perennial rivers form the environmental templates on which the earliest urban societies nucleated. On long time scales, rivers migrate by relatively abrupt changes in their course called avulsions. River avulsions have long been considered important in the development of early complex society. It is commonly accepted that settlements are clustered near active rivers and that river avulsion leads to settlement abandonment. 4500 years ago, the Indus Civilisation developed one of the most extensive urban cultures in the Old World (much more extensive than either the Egyptian or the Mesopotamian civilization). This civilisation was established on the alluvial plains of the Indo–Gangetic basin in northwestern India and Pakistan.

Lothal Dockyard / Raveesh Vyas / CC-BY-SA 2.0

The Indus Civilisation has long been considered river-based, with two of its largest and best-known cities, Harappa and Mohenjo-Daro, located adjacent to large perennial Himalayan rivers – the Ravi and the Indus, respectively. However, the largest concentration of Indus settlements is located near the divide between the Ganges–Yamuna and Indus river systems in India and Pakistan, far from major active rivers. There is an inactive river course around which these settlements are grouped which was thought to be the mythical river Saraswati. The drying up of the river that formed the Ghaggar–Hakra channel has been suggested as a major factor in the decline and abandonment of Indus urban centres in the region.

Analysis of the sediments on the river bed and satellite imagery showed that a major Himalayan river was not contemporaneous with Indus settlements in the Ghaggar–Hakra region and did not sustain the Indus Civilisation in this region. The locus for the abundant Indus Civilisation urban settlements along the Ghaggar–Hakra channel was the relict, underfilled topography of a recently abandoned valley of the Himalayan Sutlej River rather than an active Himalayan river. This abandoned incised valley was an ideal site for urban development because of its relative stability compared to Himalayan river channel belts that regularly experience devastating floods and lateral channel migration.

Water canal for the Great Bath,
Mohenjo Daro / Quratulain
CC-BY-SA 3.0

The abandoned river channel became fed by sedminents from ephemeral monsoon-fed rivers derived from the Himalayan foothills, likely the equivalent of the modern Ghaggar River and its tributaries. Indus urban settlements in the region were thus likely sustained by monsoons. This and the potential to pond flood waters in the topographic depression formed by the valley likely offered favourable conditions that led Indus populations to preferentially settle along the incised palaeovalley. A study suggested that decline in monsoonal rivers due to weakening of the Indian summer monsoon was responsible for the decline in the civilization.

River dynamics controlled the distribution of Indus sites in the region, but in the opposite sense to that usually assumed: it was the departure of the river, rather than its arrival, that triggered the growth of Indus urban settlements here. A stable abandoned valley, still able to serve as a water source but without the risk of devastating floods, is a viable alternative model for how rivers can nucleate the development of ancient urban settlements.

Acknowledgment : This post is entirely based on and edited from the article : 

Counter-intuitive influence of Himalayan river morphodynamics on Indus Civilisation urban settlements.

Production in the Indus Valley Civilization..

Agrarian base

A stable system of agriculture, supplemented by animal husbandry, hunting and plant gathering, provided economic sustenance to urban networks.

Well at Indus Valley Civilisation site, Rupnagar,
Punjab / Harvinder Chandigarh / CC-BY-SA 4.0

A ploughed field was revealed through excavation at Kalibangan. The Kalibangan field contained two sets of furrows crossing each other at right angles, thus forming a grid pattern, and it is likely that two crops were raised in the same field. In modern fields in that zone, mustard is grown in one set of furrows and horse gram in the other. Mixed cropping is suggested by other evidence as well as, for instance, in the mixture of wheat and barley at Indus sites. Such mixed cropping is practiced even today in many parts of north India as an insurance against weather hazards so that if wheat fails to ripen, the hardier barley is sure to yield a crop.

Cultivated crops included wheat, barley, rice, millets, peas, lentils, chickpeas, sesame, flax, legumes and cotton. Cattle meat was the favourite animal food of the Indus people and cattle bones have been found in large quantities at all sites that have yielded bones. In addition to their meat, cattle and buffaloes must have supported agricultural operations and served as draught animals. Mutton was also popular and bones of sheep/goat have been found at almost all Indus sites. Hunting of animals was also carried out. 

Manufacturing and Trade

Bullock cart, 2000 BC / Yann / CC-BY-SA 4.0

Inhabitants of the ancient Indus River Valley developed new techniques in metallurgy—the science of working with copper, bronze, lead, and tin. Harappans also made intricate handicrafts using semi-precious gemstone Carnelian. They worked on shells, and shells used in their crafts have origins from as far away as the coast of modern-day Oman.

Several constructions have been identified as workshops or industrial quarters and some of the buildings might have been warehouses. An Impressive workshop, recognized as Bead Making Factory, was found at Channu Daro city, which included a furnace. Shell bangles, beads of many materials, stealite seals and metal works were also manufactured at Channu Daro. Harappan seals were made generally in bigger towns which were involved with administrative network.

Statue production, and skilled metal working (in both bronze and precious metals) has been uncovered in Rakhigarhi. A gold foundry with about 3000 unpolished semi-precious stones has been found here.

Mold of Seal, Indus valley civilization, 2500 BC
Ismoon / CC-BY-SA1.0

Signs of flourishing trade can be seen by the excavation of stamps, jewellery and 'chert' weights. 

Trade focused on importing raw materials to be used in Harappan city workshops, including minerals from Iran and Afghanistan, lead and copper from other parts of India, jade from China, and cedar wood floated down rivers from the Himalayas and Kashmir. Other trade goods included terracotta pots, gold, silver, metals, beads, flints for making tools, seashells, pearls, and colored gemstones, such as lapis lazuli and turquoise.

The First Great Urbanized Culture in the World...

A distinct urban stamp

Distinct characteristics ofurban planning from remains of the cities of Harappa, Lothal, Dholavira, and Mohenjo-daro in the Indus Valley Civilisation (in modern-day northwestern India and Pakistan) lead archeologists to interpret them as the earliest known examples of deliberately planned and managed cities. The streets of many of these early cities were paved and laid out at right angles in a grid pattern, with a hierarchy of streets from major boulevards to residential alleys. 

Secondary streets are about half the width of the main streets; smaller alleys are a third to a quarter of the width of the main streets. The street layout shows an understanding of the basic principles of traffic management, with rounded corners to allow the turning of carts easily. The drains are covered. 

Drainage at Lothal / Vu2sga / CC-BY-SA 3.0

Archaeological evidence suggests that many Harrapan houses were laid out to protect from noise and to enhance residential privacy; many also had their own water wells, probably both for sanitary and for ritual purposes. These ancient cities were unique in that they often had drainage systems, seemingly tied to a well-developed ideal of urban sanitation.

Harappans demonstrated advanced urban architecture with dockyards, granaries, warehouses, brick platforms, and protective walls. These massive walls likely protected the Harappans from floods.

Harappans were among the first to develop a system of standardized weights and measures. The consistency of brick size across cities also suggests unity across the various urban areas, which is evidence of a broader civilization. The cities across a million+ square kms were interlinked by trade and economic activities, religious beliefs and social relationships, apart ofcourse from a shared high standard of living where sanitation, hygiene and an orderly life in the city was concerned. 

Although some houses were larger than others, Indus civilization cities were remarkable for their apparent egalitarianism. For example, all houses had access to water and drainage facilities. One gets the impression of a vast middle-class society.

From the big to the small

Dholavira, part of sandstone pillar, 2500 BC
/ Rahul Zota / CC-BY-SA 4.0

Urbanism in the Indus Civilisation is associated with the development of five large settlements considered by archaeologists as cities, and numerous smaller urban settlements. Three of these cities are in present day Pakistan – Mohenjo Daro, Harappa, Ganeriwala; and Dholavira and Rakhigarhi in India.

These were cities of monumental dimensions like Mohenjodaro, Harappa, Dholavira and Rakhigarhi that stand out on account of their size (more than 100 hectares each).

The intermediate tier of the urban hierarchy was made up of sites that in several features recall the layout of the monumental cities of the civilization but are smaller in size. Kalibangan, Lothal, Kot Diji, Banawali and Amri are some of them and they can be considered as provincial centres.

Dancing Girl of Mohenjo Daro /
Joe Ravi / C_BY_SA 3.0

The third tier of the Harappan settlement hierarchy is made up of small urban sites. These show some evidence of planning but no internal sub-divisions. Notwithstanding their size and structurally unprepossessing character, they had urban functions. Allahadino in Sind is one such site, which had a diameter of only 100 metres but was an important metalcrafting centre. Similarly, Kuntasi in Gujarat is a small Harappan fortified settlement where semi-precious stones and copper were processed.

Finally, urban centres were supported by and functionally connected with rural hinterlands of sedentary villages and temporary / semi-nomadic settlements. 

Sanitation in the Indus Valley Civilization

The world's first urban sanitation systems can be seen in the Indus Valley Civilization. Within the city, individual homes or groups of homes obtained water from wells. From a room that appears to have been set aside for bathing, waste water was directed to covered drains, which lined the major streets. 

The ancient Indus systems of sewage and drainage developed and used in cities throughout the Indus region were far more advanced than any found in contemporary urban sites in the Middle East and even more efficient than those in many areas of Pakistan and India today. 

Great Bath of Mohenjo Daro /
Usman_Ghani / CC-BY-SA 3.0

Mohenjo Daro’s Great Bath, built 2500 years before the roman baths, is the earliest public water tank in the world ! Drains and water chutes in the upper storeys of buildings were often built inside the wall with an exit opening just above the street drains. Tapered terracotta drainpipes were used to direct water out to the street (something we see again in the Roman Empire 2500 years later..). Many houses had distinct toilets, separate from bathing areas. Commodes were large sump pots sunk into the floors. Garbage bins were provided along the major streets as were manholes, to clean the drains. 

How old is the Indus Valley Civilization ?

Prologue

Street of Mohenjo Daro /
Quratulain / CC-BY-SA 3.0

I saw the feature film Mohenjo Daro a few days ago. Unlike what critics said at the time of its release, I found it to be fairly authentic in treatment of the setting of the Indus Valley Civilization. I then chanced upon this lovely little clip on the city by the national geographic.

Another little clip, teaching history to Indian students in Hindi, was nice too : though he is wrong in stating there were no cows in the Indus Valley Civilization.

And here, a video by the famous Khan Academy. The guy who started the Khan Academy is Salman Khan - an American of South Asian origin (father from Bangladesh, mother from India, and wife from Pakistan !) whose educational videos on various subjects have been watched 1.5 billion times. 

In the times of the Swachch Bharat Abhiyan and contesting histories, I felt the need to study the Indus Valley Civilization more - the earliest civilization in South Asia..

Timeline of the Indus Valley Civilization

9000 years ago : Signs of the early civilization have been found near the Ghagra-Hakra rivers from 9,000 years ago called the pre-harappan phase.

Picture of Mother Godess figurine /
Quratulain / CC-BY-SA 3.0

The earliest farming was developed by semi-nomadic people using plants such as wheat and barley and animals such as sheep, goats and cattle. Houses were simple mud buildings. Numerous burials show goods such as baskets, stone and bone tools, beads and bangles. Ornaments of sea shell, limestone, turquoise, lapis lazuli and sandstone have been found, along with simple figurines of women and animals. Sea shells from far sea shore and lapis lazuli found as far away as present day Badakshan, Afghanistan shows good contact with those areas.

7500 years ago : Artefacts from 7500 years ago show much evidence of manufacturing activity and more advanced techniques used. Technologies included stone and copper drills, updraft kilns, large pit kilns and copper melting crucibles. There is further evidence of long-distance trade. Mud brick houses have been found at Bhirrana settlement in Haryana, close to the presently dried up Ghaggar-Hakra river bed, with advanced material culture including arrow heads, rings and bangles of copper; beads of carnelian, jasper, and shell; and bull and female figurines. Ceramics with geometric, floral and faunal motifs were also found. The first button seals were produced from terracotta and bone and had geometric designs. Settled populations expanded in this phase.

Indus Valley Civilization, 3000 BC / Nomu420 /CC-BY SA-3.0

5500 years ago : The Early Harappan Phase began 5500 years ago and the earliest examples of the Indus script date to this time. Trade networks linked this culture with related regional cultures and distant sources of raw materials, including lapis lazuli and other materials for bead-making. By this time, villagers had domesticated numerous crops, including peas, sesame seeds, dates, and cotton, as well as animals, including the water buffalo.

4500 years ago : Early Harappan communities turned to large urban centres 4500 years ago, from where the mature Harappan phase started. Flood-supported farming led to large agricultural surpluses, which in turn supported the development of cities. The development of advanced cities coincides with a reduction in rainfall, which may have triggered a re-organisation into larger urban centers. Indus Valley people migrated from villages to cities. Large walled settlements were built, and trade networks expanded. The increasing integration of regional communities into a "relatively uniform" material culture in terms of pottery styles, ornaments, and stamp seals with Indus script was seen.  A sophisticated and technologically advanced urban culture became evident in the Indus Valley Civilisation.

Bullock cart driver, 2000 bc /
Yann / CC-BY-SA 4.0

4000 years ago : Around 4000 years ago signs of a gradual decline began to emerge, and by around 3500 years ago most of the cities had been abandoned. Recent examination of human skeletons from the site of Harappa has demonstrated that the end of the Indus civilisation saw an increase in inter-personal violence and in infectious diseases like leprosy and tuberculosis.

According to historian Upinder Singh, "the general picture presented by the late Harappan phase is one of a breakdown of urban networks and an expansion of rural ones."

The late Harappan phase witnessed large-scale de-urbanisation, drop in population, abandonment of established settlements, violence and even the disappearance of the Harappan script, the researchers say.