Shareen Joshi has this interesting summary of her paper co-written with two others.
They show how a court ruling of cleaning Ganga in Kanpur led to substantial health benefits:
In response to a writ petition against pollution of the river Ganga due to industrial waste, the Supreme Court of India in 1987 mandated the tanneries in Kanpur, Uttar Pradesh to either clean up or shut down. This column finds that the ruling resulted in a significant drop in river pollution, which in turn reduced infant mortality in the city.
The story of this court ruling began in 1985 in the pilgrimage city of Haridwar, along the Ganga; a matchstick tossed by a smoker resulted in the river catching on fire for more than 30 hours, due to the presence of a toxic layer of chemicals produced by a pharmaceutical firm (Mehta 2009). In response to this incident, environmental lawyer and social activist M.C. Mehta filed a writ petition in the SC charging that government authorities had not taken effective steps to prevent environmental pollution of the waters of the Ganga. The scale of the case – the whole 2,500-km stretch of the river – proved to be intractable. So the Court requested Mr. Mehta to narrow down his focus and he chose the city of Kanpur, despite neither being from the city nor living there. In Mehta’s words, “It (Kanpur) was in the middle of the Ganga basin; the reddish colour of the pollution made the pollution highly salient, and the city seemed representative of many other cities in the Ganga Basin.” (Mehta 2014)1
For more than 100 years, Kanpur has been a major centre for India’s tannery industry. Most of the tanneries are located in the neighbourhood of Jajmau, which lies outside the main city on the southern bank of the Ganga. The leather industry is highly polluting; the processes of washing, liming, fleshing, tanning, splitting and finishing involve a large number of chemicals. One tonne of hide generally leads to the production of 20-80 m3 of turbid and foul-smelling wastewater, including chromium levels of 100–400 mg/l, sulfide levels of 200–800 mg/l, high levels of fat and other solid wastes, as well as significant pathogen contamination. Pesticides are also often added for hide conservation during transport (Cheremisinoff 2001). Tannery effluent is generally characterised by its strong colour (reddish or dull brown), high levels of biochemical oxygen demand (BOD), high pH, and large amounts of dissolved solid wastes.
The 8-10 respondents in Mr. Mehta’s petition included all 75 tanneries of the Jajmau district the Union of India, the Chair of the Central Pollution Control Board (CPCB), the Chair of the Uttar Pradesh State Pollution Control Board (SPCB), and the Indian Standards Institute. The petition also claimed that the Municipal Corporation of Kanpur was not fulfilling its responsibilities. The Court subsequently bifurcated the petition into two parts. The first dealt with the tanneries of Kanpur and the second with the Municipal Corporation. These are now called Mehta I and Mehta II in legislative digests, and became the “Ganga Pollution Cases” – the most significant water pollution litigation in the Indian court system.
By October 1987, the SC had invoked the Water Act and Environment (Protection) Act, as well as Article 21 of the Indian Constitution (which protects an individual’s right to life), to rule in Mr. Mehta’s favour. It ordered the tanneries of Jajmau to clean their wastewater within six months or shut down entirely. This was followed by a January 1988 judgment that required Kanpur’s local municipality to take several immediate measures to control water pollution: relocation of 80,000 cattle housed in dairies or safe removal of animal waste from these locations; cleaning of the city’s sewers; building of larger sewer systems; construction of public latrines; and an immediate ban on the disposal of corpses into the river. The court order also required all schools to devote one hour each week to environmental education and awareness.
They test this intervention and figure big decline in pollution levels which lead to higher IMR..
I would have been surprised if the results showed no improvement. We have very little idea on how polluted the water is in India. This was 1985 and things have only gone downhill in last 30 years.