How India Must Plug its Leachate Problem

October 29, 2026

India’s landfill problem is often measured in tonnes of waste, but that captures only half the story. As rainwater and moisture move through layers of decomposing garbage, they pick up organic and inorganic pollutants, creating leachate. If not properly collected and treated, the toxic liquid can seep into soil and groundwater, altering their chemistry and carrying contaminants to wetlands and farmland. The risks are particularly significant in a country where more than half the municipal waste is biodegradable and a large quantity is dumped in open landfills and wasteland. The question then arises: is India able to manage leachate effectively? Young leachate has high levels of biodegradable organic pollutants, reflected in elevated chemical oxygen demand (COD) and bioch-emical oxygen demand (BOD). As the landfill ages, the BOD/COD ratio decreases. Mature leachate is characterised by relatively high ammoniacal nitrogen concen-trations and greater proportions of humic and other recalcitrant organic substances. The dissolved concentration and mobility of many heavy metals, including copper, zinc, lead, chromium and cadmium, generally decline with leachate maturation, but their persistence and mobility remain dependent on sitespecific geochemical conditions, including pH and interactions with dissolved organic matter. At Delhi’s Ghazipur landfill, studies have already found hazardous substances and heavy metals like cadmium in ground-water at concentrations exceeding limits for drinking water. Before delving into experience across the country, let’s note the complex and changing nature of leachate. It forms as organic waste decomposes and oxygen is exhausted, triggering anaerobic processes that generate methane, volatile fatty acids and dissolved organic carbon. As water moves through waste it carries the compounds with ammonia, humic substances and heavy metals. The contaminant profile is also becoming more complex. Studies globally have shown presence of pharmaceutical products, micro-plastics and per- and polyfluoroalkyl substances (PFAS) in leachate. Pharmaceutical residues and biomedical waste may contribute to proliferation of antibioticresistant bacteria and resistance genes. To assess whether the complex nature of leachate is recognised and contained in India, the authors of this article estimated leachate generation in the country. Using thumb rules cited in existing literature, the benchmark was set at a lower-threshold value of 50 litres of leachate per tonne of waste per day. The assessment indicates that major cities including Delhi, Mumbai, Hyderabad and Bengaluru likely generate high volumes of leachate given their massive daily waste generation and ageing landfills. Next comes an analysis of collection and treatment systems. Here, cases suggest gaps even in con-ventional mechanisms. For example, at the Bandhwari landfill in Gurugram and Faridabad, a September 2025 inspection ordered by the National Green Tribunal (NGT) recorded untreated leachate overflowing into plantation and forest areas through temporary kutcha drains and concrete pipes. The site lacked gar-land drains (perimeter channels to intercept and divert surface run-off), and none of its three storage ponds had impervious lining. The leachate was reportedly transported to the Behrampur sewage treat-ment plant, but the quantity was lower than estimated generation. Leachate is a liquid pollution that forms when water, such as rain or snow, percolates through landfills. As the water travels through the waste, it picks up various contaminants, resulting in a highly toxic liquid. This leachate contains a mix of harmful chemicals that pose significant threats to the environment and human health. Among these contaminants are a group of particularly dangerous substances known as polyfluoroalkyl substances (PFAS). Leachate is a major environmental hazard. When leachate seeps from landfills, it can contaminate soil and groundwater. This pollution can harm plant and animal life, disrupt ecosystems, and degrade natural habitats. The presence of PFAS in leachate is especially concerning. PFAS are persistent chemicals that do not break down in the environment, leading to long-term contamination. These chemicals can accumulate in the food chain, causing widespread ecological damage. The health risks associated with leachate are profound. Leachate often contains heavy metals, organic compounds, and other toxic substances that can have serious health effects. PFAS, in particular, have been linked to various health issues, including cancer, liver damage, and developmental problems in children. When leachate contaminates drinking water sources, it poses a direct threat to human health. Moreover, when this contaminated water is used for agricultural purposes, the toxins can enter the food supply, further endangering public health. When leachate reaches wastewater treatment facilities, it undergoes the same treatment processes as regular sewage. However, most wastewater treatment plants are not equipped to remove PFAS and other persistent chemicals effectively. As a result, these harmful substances can end up in the treated water that is released back into rivers, lakes, and oceans. Additionally, the sludge left over from the treatment process, which can still contain significant amounts of toxins, may be used as fertilizer, further spreading contamination. PFAS are synthetic chemicals used in a variety of industrial and consumer products for their water and grease-resistant properties. However, their stability and resistance to degradation make them incredibly persistent in the environment. Once released, PFAS can remain in the soil and water for decades, continuously posing health and environmental risks. This persistence, combined with their ability to accumulate in living organisms, makes PFAS a significant concern for both current and future generations.