Recurring tensions have long set India and Pakistan at odds over the Indus River system they both share. As the downstream neighbor, Pakistan fears that Indian infrastructure or diversions on the river could diminish its water supply, undermining its economy and jeopardizing its food security. As the upstream riparian, India worries that Pakistani caveats and cavils against planned and prospective water projects constrain its ability to develop its own natural resources. As ballooning demands bump against the limits of renewable supplies in the basin, analysts in India, Pakistan, and beyond warn that growing competition over the Indus waters could exacerbate already fraught relations between the two nations, perhaps even sparking open conflict.
Yet while prospective water supply clashes increasingly exercise policy imaginations on both sides of the border, water quality rather than water scarcity now poses by far the greater risk to the lives and welfare of Indians and Pakistanis living on the Indus. Agriculture, industry, mining, and other activities increasingly load surface and groundwater resources with synthetic chemicals, fertilizers, pesticides, toxic metals, and microbial pathogens that endanger human health and imperil vital ecosystems. According to the United Nations Environmental Programme, some 55 cubic kilometers (km3) of wastewater are dumped into the Indus every year. By way of comparison, the average annual flow of the entire river amounts to 187 km3.
Agriculture accounts for most water pollution in both the Indian and Pakistani portions of the Indus. Ever since the Green Revolution swept across South Asia during the 1960s and 1970s, fertilizers and pesticides have been widely used to enhance crop production. Although they can augment harvests, these chemical compounds also contaminate agricultural runoff, which pollutes adjacent waterways, seeps into groundwater stocks, and taints drinking water supplies for consumers and communities downstream. As India and Pakistan expand their agricultural output to feed growing populations in coming years, more agricultural effluents will drain into Indus water systems. According to the Organisation for Economic Cooperation and Development, as India boosts its crop production by some 50 percent by 2030, annual nitrogen loads in the country's wastewater will soar fivefold and phosphorous loading will more than triple over year 2000 levels.
Industrial pollution is similarly widespread. On the Indian side of the basin, a 2011 UN report named Haryana and Punjab as particular "hot-spot states" for water pollution stemming from power-generation, manufacturing, and other heavy industries. Available data on Pakistan suggest that 99 percent of industrial sewage is discharged into streams and canals untreated. Industrial water use also upsets the Indus Basin's environmental health. In both India and Pakistan, energy producers withdraw large volumes of water to cool power plants; this water is often returned to the basin's waterways at high temperatures, disturbing riverine ecosystems and disrupting freshwater fisheries.
Municipal wastewater constitutes the third principal source of pollution in the Indus. Often characterized by alarming levels of bacterial contamination, raw municipal sewage is a primary driver of waterborne illnesses - such as diarrhea, typhoid, intestinal worms, and hepatitis - in downstream populations. Little of the basin's municipal effluents are properly treated. In Indian cities of 50,000 to 1 million people, wastewater facilities can handle less than one-third of the sewage generated daily. In Pakistan, more than 90 percent of municipal wastewater goes untreated. With urban populations projected to swell 62 percent in India and 83 percent in Pakistan by 2030, cities' poorly maintained water delivery systems will face further strain, while overburdened wastewater facilities will be pushed far past their capacity.
The consequences of pervasive water pollution for Indian and Pakistani societies are dire. In India, a national water and sanitation survey conducted by the Ministry of Urban Development judged not a single city "healthy," while nearly half were deemed on the brink of public health emergency. In Pakistan, a five-year nationwide study found water quality fell below recommended standards for human consumption in 76-96 percent of the samples tested across the country. All told, water pollution and inadequate sanitation costs Pakistan USD$5.7 billion annually in health damages, productivity losses, and work and school absences, a sum equivalent to 3.9 percent of GDP. Similarly, inadequate sanitation costs India USD$53.8 billion annually, representing 6.4 percent of GDP. More troubling than the economic impacts is the human toll. Water-borne diseases account for 20 to 40 percent of all hospital patients and one-third of all deaths in Pakistan, including an estimated 200,000 to 250,000 Pakistani children who perish from diarrhea and other water-related illnesses each year. In India, unsafe water and inadequate sanitation cause 10 percent of all deaths, including more than 30 percent of deaths among children under five. Diarrhea alone killed 395,000 Indian children in 2006.
Water quality in the Indus Basin represents a shared challenge for the riparians. Though Pakistan lies largely downstream from India, the Indus forms the border between the two countries for more than 100 miles - via its tributaries, the Ravi and the Sutlej - such that pollution from each country impacts the other. So too, shared surface water sources partially overlap hydrologically with shared groundwater aquifers in the Indus system, such that pollution in one water supply may potentially contaminate the other. Indeed, the myriad pressures on water quality in the basin ultimately interact with strains on water quantities. Decreasing water quality can lower effectively available water supplies, as some sources become too degraded for certain uses. Extreme industrial pollution, for example, can render water supplies unsuitable for drinking, irrigation, and even for other industrial uses. Likewise, as withdrawals from the Indus increase, diminishing water quantities boost the concentration of any pollutants present, further eroding water quality.
Despite the importance to water users of water quality as well as quantity, water relations between India and Pakistan have largely focused on regulating the river flows that reach the two countries. The 1960 Indus Waters Treaty physically divides the river between the two nations, allotting use of the three eastern tributaries to India and the three western tributaries to Pakistan. The agreement addresses water quality in a single hortatory passage pledging the parties' intent to prevent undue pollution "as far as practicable," foregoing any more specific or more binding stipulations. Yet both countries could benefit from greater collaboration in tackling their common water quality problems. Water managers across the basin face similar risks from agricultural wastewater, municipal sewage, and industrial effluents. Enhanced monitoring and data exchange would substantially increase their ability to apprehend the nature and extent of these challenges. By the same token, sharing policy lessons and technical advances in water treatment, re-use, and recycling, would combat the spread of pollution by spreading innovations and best practices. Greater cooperation can help India and Pakistan ensure that all their citizens enjoy safe and sustainable water supplies from the Indus.