The government says that poor people living along the Yamuna are the problem. But the fact is that s/he who uses the most water also generates the most waste. The situation in India's capital city is shameful in this regard. The bulk of the water goes to the rich and powerful, with the majority population getting less than survival quotas of water. Therefore, it is the water users who generate waste. If water use is the criterion for a pollution inventory, then it is clear that the rich, not the poor and unconnected or unserviced, are the cause of the river's condition.

What does treatment cost? The issue, then, is: what is the cost of wastewater treatment? Who pays for pollution control? The water users in the city are connected to the sewer system, their waste is transported long distances to STPs and then treated, before disposal. More water means more money to clean up waste. There are really no estimations on this waste bill of the city.

What can be estimated is on the basis of the capital and running costs of STPs. On checking with agencies, it was found that an STP in Delhi costs between Rs 20 lakh to Rs 66 lakh per million litres of waste treated per day (mld). This cost varied with the technology used and the quality of treatment. But on an average, an STP costs roughly Rs 40 lakh per mld.

What, then, would be the average cost per person? This would depend on the amount of water a person uses and so the waste s/he discharges. If the person gets water supply at 60 litres per capita per day (lpcd), s/he will generate 48 litres of waste per day. In this case, a one mld plant will treat the waste of 20,000 people, at a capital cost of Rs 40 lakh per mld. In this case, the cost each person must pay would be Rs 200 for the capital cost of plant.

But the same equation changes, as water use changes. At the Delhi rate of water supply, 200 lpcd, the same plant will treat the waste of only 6,250 people. In this case, the capital cost per head will be Rs 640 and the city would need to build more STPs.

It also costs to operate and maintain these plants. The treatment costs range between Rs 0.40 to Rs 2.5 per kilolitres depending on the technology adopted and cost recovery possible from the STP .

So water saved is money saved, literally. If water users in Delhi do not pay for their water and waste, in this political economy of defecation, they are being subsidised to excrete in convenience. To the inconvenience of us all. And the river.