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.
India's rivers are heavily polluted. Cleaning them up has been the subject of multiple regulatory and legislative initiatives, but it is not clear whether any of these initiatives have been successful (Greenstone and Hanna 2014).
One of the most polluted sites
Ganga pollution cases
The story of this court ruling began in 1985 in the pilgrimage city of Haridwar,
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
The 8-10 respondents in
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
Impact on pollution and health risk
We analyse data from demographic surveys, pollution monitors, and the geospatial coordinates of rivers to identify the impact of the court ruling policy on river pollution and health risk2. The period of analysis is 1986-20043.
Our first approach exploits the novelty and timing of the SC ruling: comparing districts upstream versus downstream of Kanpur and before and after the SC verdict, we look at the impact of the SC verdict on both pollution and health outcomes. As a measure of river pollution, we use BOD, which is appropriate in our context because (i) it is systematically measured by the river pollution monitors, and (ii) it is sensitive to various types of pollutants that constitute a health risk. Infant mortality is our main health outcome variable. Being most vulnerable to pollution, infants are the group for which we expect to detect the biggest impact. Second, our choice is also driven by data availability as surveys with complete birth histories allow us to construct a full mortality history for every child ever born. On the other hand, other health outcomes (such as acute illnesses or diarrhoeal diseases) are recorded for the specific time window in which the survey is being conducted. This thus limits the number of observations one could obtain for any given child.
We find evidence of a significant drop in both river pollution and health risk. On the pollution front, the ruling increases the likelihood of the river water in the area around the tanneries being in the ‘fit-for-bathing’ category by 40%. In terms of health risk, our results indicate that mortality among
Next, we explore the channels of impact. While we document a drop in pollution, the concurrent decline in infant mortality could well be driven by alternative channels, such as increased awareness and pollution avoidance among Indian households in the aftermath of the verdict. To assess the empirical relevance of alternative channels, we look at whether the Court ruling has any residual explanatory power with respect to infant mortality once the effect of reduced pollution has been accounted for. To do so, we first acknowledge that pollution might be associated with other risk or mitigating factors, whereby more polluted areas might also be areas with higher economic growth, higher levels of education, better access to health services, etc. A correlation between pollution and infant mortality might then be driven by the correlation between pollution and one of these underlying factors, which would severely affect the interpretation of our results. To address this problem, we use the property that pollution flows downstream. Under the plausible assumption that upstream pollution levels are uncorrelated with other risk and mitigating factors downstream, we can isolate in our pollution measure the component that is influenced by upstream pollution but not by any of the aforementioned risk and mitigating factors of infant mortality. As a result, the correlation between infant mortality and this adjusted measure of pollution can be interpreted as the impact of pollution on our health outcome.
When we fully account for the effect of pollution on health, we fail to detect any residual effect of the SC ruling on infant mortality. In other words, our empirical analysis suggests that all the impact of the SC ruling on infant mortality if fully explained by its impact on river pollution, leaving little room for other mechanisms to have played a role.
- This is based on a personal interview I conducted with Mr Mehta.
- (i) Demographic data are drawn from the District Level Household Survey of India (DLHS), 2002. (ii) Pollution data are a subset of data from India’s national water quality monitoring programme culled from a combination of online and print records of CPCB online and print records. These data were originally gathered and used by Greenstone and Hanna (2012). (iii) Data on rainfall are from the University of Delaware. Air temperature averages are from the Indian Meteorological Institute. GIS (geographic information system) maps are used to locate pollution monitors and measure the distances between monitors. (iv) Locations of municipal sewage treatment capacity and the incidence of major river cleanup policy, as reported in the CPCB annual reports for all pertinent years of our sample (1986—2002), are used.
- This is because our most recent infant mortality data are from 2004 and our earliest pollution data are from 1986.
- The results are unaffected whether we restrict our time window to mortality rates prior to 2000 or to 1995.
- Cheremisinoff, NP (2001), Handbook of pollution prevention practices, CRC Press.
- Greenstone, M and R Hanna (2014), “Environmental Regulations, Air and Water Pollution, and Infant Mortality in India”, American Economic Review, 104(10), 3038-3072.
- Do, Q, S Joshi and S Stopler (2016), ‘Environmental policy, river pollution, and infant health: Evidence from Mehta vs. Union of India’, IGC Working Paper.
- Mehta, MC (2009), In the Public Interest: Landmark Judgements & Orders of the Supreme Court of India on Environment & Human Rights, Prakriti Publications.