Thirsty Places: Delhi

The tanker comes at four in the afternoon, when it comes, and the lane in Sanjay Camp has been waiting since the morning. Jerrycans stand in a line along the wall in the order their owners arrived; when the truck turns in, the line dissolves, the hoses come out of the back, and for twenty minutes the lane is a fight conducted with buckets, a boy on the roof of the tank working the valve, a woman with three cans and a child, an old man who will get what is left. The truck is from the Delhi Jal Board, the city's water board, and it is free; the one that comes on the days it does not is private, and charges. This is how a share of the capital of India gets its water, in a city of more than thirty million people, in a country that has put a lander on the moon, and in May, when the temperature is forty five degrees and the river is low, it is how a larger share gets it.

This article is about where Delhi's water comes from and why the summer is a crisis every year, what the river looks like below the city and why, who runs the tankers, what the groundwater did when the wells outran the rain, and why the city that sends its sewage to the Yamuna is the one that drinks from it.

The river that arrives divided

Delhi stands on the Yamuna, the largest tributary of the Ganga, which comes down from the Himalaya through Haryana and reaches the city at Wazirabad, where the board's oldest works takes it. By the time it arrives it has been divided. At the Hathnikund barrage, two hundred kilometres upstream, the river is split between the canals of Haryana and Uttar Pradesh under an agreement of 1994, and what reaches Delhi in a dry May is a share that the states argue over every year and that in 2024 went to the Supreme Court, which ordered Haryana to release more and Haryana said it had none to release. The river at Wazirabad in late spring is a shallow, slow channel, and the city's works there have been shut, some years, because the ammonia in the water arriving from the drains upstream was too high to treat.

The rest comes by canal and from the ground. The Upper Ganga Canal brings Ganga water from the east to the works at Sonia Vihar; the Munak canal, which runs through Haryana, brings Yamuna water the city is entitled to from the barrage, and the arguments about how much of it leaks or is taken on the way are the arguments of every summer. And the wells, the board's own and the hundreds of thousands of private ones, which the groundwater article on this site has the mechanism for, supply the rest and more than the rest in the districts the pipes do not reach.

The tankers

The gap between what the board supplies and what the city uses is filled by trucks. The board runs about a thousand tankers of its own, free, to the unauthorised colonies and the camps the pipes do not reach, and the private operators run thousands more, filling from borewells on the city's edge that are in many cases illegal, and selling by the tank to the households, the apartment blocks, the hotels and the factories whose pipes run dry. The business is large enough and lucrative enough that the newspapers call it the tanker mafia, and the term is not only rhetoric: the police have charged operators with stealing from the board's own pipelines and with running wells the board has sealed, and the price of a tank rises with the temperature. A household in a camp that gets its water by tanker pays, per litre, many times what a household with a metered pipe pays, which is the pattern the Lagos and Karachi articles on this site have met, and it pays it to a system that depends on the shortage continuing.

The wells

Delhi's south and west were built on groundwater. The aquifer under the ridge and the plain was close to the surface a century ago, and the city that spread over it after 1947, and faster after 1990, drilled wells for every block of flats and every farmhouse that the pipes did not serve, and the water table fell as the pumping outran the monsoon's recharge, by a metre a year in the districts the ground water board surveys, to depths of a hundred metres and more in the south. The deeper wells draw older, saltier water; the shallow ones dry in May; and the government's water index of 2018 named Delhi among the cities that would exhaust their accessible groundwater within a few years, which has not happened in the way the headline said because the wells went deeper. The rainwater harvesting article on this site describes the tanks that the city has required on every new building since 2001 to put the monsoon back into the ground, which works where it is done and is done in a fraction of the buildings it covers.

The drain

Below Wazirabad the river changes. The twenty two kilometres of the Yamuna through the city, between the barrage where the water is taken and the barrage at Okhla where it leaves, are about two percent of the river's length and receive, by the pollution board's count, most of its pollution: the city's sewage, from eighteen major drains, of which the Najafgarh drain alone carries more than half, treated in part and in large part not. The river in that stretch has, for most of the year, no dissolved oxygen at all, which the BOD article on this site explains is the condition of a sewer rather than a river, and at Okhla, where the water falls over the barrage, the phosphate from the city's detergents whips into a foam that stands a metre deep on the surface, white and drifting, in which the devout stand to pray at the festival of Chhath each November, because the river is sacred and the festival requires it. The pictures go round the world every year.

The city has been building sewage works since the 1980s and has, on paper, the capacity to treat most of what it produces; what it lacks is the sewers. The drains that carry the sewage were built for storm water and run to the river rather than to the works, and the colonies that have grown without permission, which hold a third of the city, have no sewers at all, so that the works run under capacity while the drains run full. The court appointed committee that reviewed the river in 2019 found that less than half of the city's sewage reached a treatment plant. The programme to intercept the drains and carry them to the works, which the after you flush article on this site would recognise as the first step a city takes, has been under way for twenty years and is the thing on which the river depends.

The flood

The same river drowns the city. The monsoon arrives in July, and in a strong year the Yamuna that was a shallow channel in May comes down from the hills at thousands of cubic metres a second, over the barrage at Hathnikund that the states argue over in spring, and into a floodplain that the city has built on. In July 2023 the river at Delhi reached its highest level in the records, above the flood of 1978, and spread through the low districts along its banks, into the lanes behind the Red Fort, over the ring road and the ghats, and into the Wazirabad works themselves, which were shut because the water that the city could not get enough of in May had flooded the pumps in July. Tens of thousands of people were moved from the floodplain colonies to relief camps. The city floods and runs dry in the same year because the river's water comes in a few weeks and the city has nowhere to keep it: the floodplain that would have held it is built on, the ponds and tanks that the old city stored the monsoon in are filled and paved, and the harvesting tanks the rule requires are a fraction of what the rule covers. A river that comes all at once needs the ground to take it, and Delhi has covered the ground.

What it teaches

Delhi is the city on this site where every water problem of the others happens at once. The river arrives divided by the states upstream and leaves as a drain; the canals cross a neighbour that argues over them; the wells have gone a hundred metres down; the pipes reach two thirds of the people and the tankers, public and private, serve the rest at a price that rises with the heat. The engineering the city needs is known and partly built, works that stand half empty, canals that leak, a harvesting rule on every building; what it lacks is the sewer to the works, the pipe to the camp and the agreement with the state next door, which are the political parts. The capital of a country that can reach the moon sends a tanker to Sanjay Camp at four in the afternoon, when it comes.

Twenty two kilometres that carry a river's pollution, a hundred metres down to the water, and a truck in the lane with a boy on the valve.