CHENNAI: Tamil Nadu is among the states worst affected by groundwater overexploitation, with 106 assessment units—33.87% of the total of 313—classified as over-exploited, according to a comprehensive report of the Central Ground Water Authority (CGWA) submitted before the principal bench of the National Green Tribunal.
The CGWA report, which was based on the data provided by every State last month in a specific format, says that, in Tamil Nadu, while No Objection Certificates (NOCs) for drawing groundwater in over-exploited and critical areas are restricted to domestic use, infrastructure development, and non-water-intensive industries, the enforcement of these norms has been inconsistent.
A total of 492 illegal groundwater extraction units were sealed in the state based on orders from the Madras High Court. However, unlike other states such as Punjab and Haryana, Tamil Nadu has yet to introduce provisions for pricing or environmental compensation for illegal groundwater extraction.
“There is no provision for collecting Environmental Compensation under existing regulations in Tamil Nadu,” the CGWA noted. “NOCs have only been issued to water-based industries located in safe and semi-critical areas, not in over-exploited ones.”
Within the State, Chennai, Salem, Coimbatore, Dindigul, Mayiladuthurai, Vellore, and Tirupattur districts are the worst affected. For instance, out of 16 groundwater assessment units in Chennai, 13 are over-exploited, which is 81.25%.
Some States in North India are trying to address the issue by clamping tariffs. Haryana has not only restricted permissions in over-exploited zones to MSMEs and drinking water projects but has also collected Rs 156.38 crore as revenue. Additionally, Rs 94.17 crore has been allocated for 21 water conservation projects in 2025-26. The state has issued over 1,850 show cause notices and sealed numerous borewells.
Punjab has gone a step further. Its Water Regulation and Development Authority (PWRDA) has imposed environmental compensation charges under its 2023 directions. By March this year, it had collected Rs 4.54 crore from 220 units as Groundwater Compensation Charges and Rs 10.12 crore from 1,281 units as non-compliance or delay charges, official data shows.
Karnataka, with 45 over-exploited taluks, has not yet enforced environmental compensation but is issuing NOCs with stringent conditions—valid only for two years and requiring 100% recharge measures. Penalties are imposed for late NOC applications and violations.
Kerala reported three blocks in the ‘critical’ category but none over-exploited. The state has taken action against 594 illegal structures and collected Rs 15.64 lakh in penalties. A proposal to impose environmental compensation is under government review. As per the consolidated guidelines to regulate and control groundwater extraction in India by CGWA dated September 24, 2020, with amendment notification dated March 29, 2023, States were advised to put a price on water and directed to impose environmental compensation on violators as illegal groundwater extraction is punishable under the Environment (Protection) Act, 1986.
Across the country, the situation is grim. The CGWA has identified thousands of assessment units in various states that are either over-exploited, critical, or semi-critical. Punjab has the highest proportion, with 115 units classified as over-exploited. Rajasthan tops in absolute numbers with 214 such units (20.86% of total), followed by Haryana (88 units, 61.54%) and Uttar Pradesh (132 units).
Meanwhile, the CGWA has pulled up eight states and Union Territories—including Delhi, West Bengal, Telangana, Pondicherry, and Jammu & Kashmir—for failing to provide requested data despite multiple reminders and a clear directive under Section 5 of the Environment (Protection) Act, 1986.
The CGWA has requested the NGT to issue directions to the defaulting states and stressed the need for urgent compliance.