Rajat Banerji | March, 2002

Every month this website examines the status of major Indian rivers. This time around, environmental journalist Rajat Banerji discovers a semblance of hope for the highly polluted Yamuna River - the most important tributary of the Ganga.

The surviving fish in the polluted Yamuna have reason to celebrate.

Because the decision to construct 12 small treatment plants in the Indian capital of New Delhi is a big step forward. Of the 2,547 million litres a day (mld) of sewage generated in the metropolis, only 885 mld (or 35 percent) is treated before being released back into the Yamuna. So the commissioning of these small STPs could improve the water quality in this beleaguered river somewhat.

But the saga of the 1,376 km river remains murky. Lifeline to some 60 million people, a mere 2 per cent of its length accounts for the bulk of pollution: 71 per cent of the wastewater problem, and 55 percent of the biochemical oxygen demand (BOD) load is released into the river daily, in fact - from New Delhi!

	The Yamuna as viewed from the Taj Mahal in Agra is seriously contaminated because of upstream pollution from Delhi

The ultimate devastation, however, occurs elsewhere. While raw water treatment plants in Delhi require 15 kgs of chlorine to treat one million gallons (mlg), their counterparts downstream at Agra require 54 kgs chlorine per mlg! The good citizens of Agra, around 200 kms from Delhi, are thus forced to imbibe high levels of chlorine, because Delhi doesn't treat the muck it generates! (Research in Europe and America suggests that imbibing high levels of chlorine can lead to colon cancer.)

A few facts
The Yamuna originates at the Yamunotri glacier 6,387 metres above mean sea level, in Uttarkashi district of Uttaranchal state. The river then meanders into the plains, some 172 kms from its source, at the Tajewala barrage, where almost all its waters are diverted into the Western Yamuna Canal and the Eastern Yamuna Canal for irrigation, urban and industrial usage. This 172 km stretch is referred to as the Himalyan segment.

The river then flows 224 kms through Haryana, between Tajewala and the Wazirabad barrage at Delhi. This is called the upper segment. The 22 km between the Wazirabad and Okhla barrages is the Delhi segment, while the 490 km stretch between Okhla barrage and the confluence with the Chambal River is known as the eutrophicated segment - so poor is the water quality in this stretch of the river.

Average value of pollutants in three locations along the Yamuna

Parameter	Upstream of Delhi	Delhi (midstream at Nizamuddin)	Standard for class 'C' surface water
Fecal coliform	251	50,185	Incl. in Tot. Coliform
Total coliform	9604	126508	5000
Dissolved oxygen	7.41	3.40	4
BOD	1.18	4.92	3

Source: 'Parivesh' - Highlights 1999, Central Pollution Control Board, p 17.
Key: Fecal and Total coliform measured in Most Probable Number (MPN) Dissolved oxygen, BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) measured in milligramme per litre
Class C surface water: drinking water source with conventional treatment

Some 80 per cent of precipitation in the Yamuna basin occurs during the three monsoon months of July, August and September. This affects the river's flow. For instance, the discharge peak during the monsoons at Okhla barrage (in the Delhi segment of the river) rises to 5,843 cubic metres per second (cbm). In the post-monsoon season, this drops to 1,767 cbm and to an astounding low of 50 cbm during the summer months. The variance of water volume is thus considerable.

The annual flow of the Yamuna is 10,000 cbm, of which an estimated 4,400 cbm is used annually. Though over 50 per cent of the river's water remains in the riverbed, seasonal variances ensure that for the most of the year, the pollution levels remain exceedingly high.

Delhi dilemma
Delhi's population, which stood at 9.37 million in 1991, is now estimated to be around 13 million, and is projected to rise to 20 million by 2010.

The Yamuna is the source of 70 per cent of Delhi's water supplies; and raw water required in 2010 would approximately be 4,030 mld, with generated sewage at around 3,920 mld.

Currently, though, Delhi has the capacity to treat only 1,153 mld sewage, while its sewerage network is capable of delivering only 885.3 mld to the STPs. Although raw water requirements for Delhi are likely to be met by water stored in the Tehri dam, sewage treatment remains a sore point.

"2,083 mld of wastewater is generated within the sewered areas of Delhi," notes a recent Central Pollution Control Board (CPCB) report. "Even in the sewered areas, all sources of wastewater (including households) are not connected to the sewerage system. As a result, a significant volume of wastewater generated remains untapped and finds its way into open drains." It comes as no surprise, then, that Delhi treats only 35 per cent of its sewage!

While it may take awhile before the policymakers of India wake up to improved technologies such as dry sanitation or "eco-san", the planned construction of small STPs is definitely encouraging. Being small, they require far less land. And given the complicated maze of Delhi's sewer's and storm water drains, smaller STPs have a better chance of working.


Rajat Banerji is an environmental researcher and journalist based in New Delhi