Ground realities: Groundwater contamination poses serious hazards

India’s reliance on groundwater as a primary source of drinking water and irrigation has grown exponentially over the years. With around 85 per cent of rural water supply and 62 per cent of the country’s irrigation needs met by groundwater, its importance cannot be overstated. However, the Annual Groundwater Quality Report 2024, released recently by the Central Ground Water Board, highlights alarming levels of contamination in groundwater across the country. Not only has groundwater been undervalued and overexploited, but its quality too has been neglected. The findings of the report suggest that almost 20 per cent of the samples exceeded the permissible limit for nitrate, while 9.04 per cent of those had fluoride levels above the limit. Arsenic contamination was found in 3.55 per cent of samples, notably in the Ganga-Brahmaputra floodplains. Quality varies considerably across Indian states. While states such as Arunachal Pradesh, Mizoram, and Meghalaya showed 100 per cent compliance with the norms set by the Bureau of Indian Standards, high contamination hotspots were identified in Rajasthan, Punjab, Haryana, and Andhra Pradesh. In Punjab, high nitrate concentrations from excessive use of fertilisers and agricultural runoff have made water unsafe for drinking. In Rajasthan, the problem is different but equally severe.

 

Groundwater contamination in India is often the result of a combination of natural and anthropogenic factors, including natural leaching of minerals, industrial discharge, unregulated mining, and excessive use of chemical fertilisers and pesticides. Increased salinity and the presence of microplastics too are problems. In urban areas, the challenge is compounded by untreated sewage and industrial effluents seeping into aquifers. Previously, studies have shown that a large share of urban groundwater samples has significant microbial contamination due to improper waste management. Poor groundwater quality has far-reaching consequences for public health. The impact on agriculture is equally concerning. Contaminated groundwater not only reduces crop yields and renders the water unsuitable for irrigation, but also introduces harmful substances into the food chain. Farmers in coastal regions, for instance, have reported reduced productivity due to salinity issues in groundwater, driven by over-extraction and seawater intrusion.

 

In this regard, improved agricultural water management can mitigate contamination. Adopting sustainable agricultural practices, promoting low-cost water filtration techniques for poor households, providing proper sewage disposal, and artificially recharging aquifers can improve groundwater levels and quality. Moreover, regional variations in contamination underscore the need for targeted intervention and localised groundwater management. Central-government programmes like the Atal Bhujal Yojana and state-level initiatives like Tamil Nadu’s rainwater-harvesting mandate in all buildings or arsenic-mitigation programmes in West Bengal are clearly not enough. It is essential to enable last-mile participants, including local institutions and community members, to take charge of decisions related to groundwater management. Establishing hydrogeological monitoring networks and forming water-security plans at gram-panchayat level can help incorporate indigenous knowledge in tackling aquifer depletion and rejuvenating groundwater quality. Initiatives like installing water meters, identifying leaks, launching public-awareness initiatives, and formalising rights to groundwater may be beneficial. Well-defined and enforceable groundwater rights, detached from land ownership, can offer solutions in this regard.