Top 10 States in India with Best Water Quality

Sharp contrasts emerge in the 2025 State-wise WQI rankings for India between the ecologically rich Northeast and the highly urban industrial belts of North and West India. Mizoram tops the list with pristine water quality, while Delhi features at the bottom, showcasing how geography, governance, and growth patterns shape India's water future.

What Do the 2025 Water Quality Rankings Show?

WQI in 2025: Ranks all 36 states and UTs on a 0–100 scale, taking into consideration parameters such as dissolved oxygen, biochemical oxygen demand, pH, and coliform counts. Higher scores imply that water is fit to drink and for irrigation purposes, according to CPCB data, NITI Aayog's Composite Water Management Index, and trends from missions such as Namami Gange and Jal Jeevan Mission.

Nearly 70% of India's water bodies are now polluted, according to reports from the Central Pollution Control Board, where more than 350 polluted stretches have been marked over 323 rivers. The rankings expose deep disparities driven by rainfall, industrialisation, sanitation, and population density.

Top 10 States with Best Water Quality (2025)

According to Central Pollution Control Board, Northeastern and coastal locations have reached the highest rankings by virtue of high rainfall, dense forests, and relatively low industrial loads.

Heavy monsoon rainfall (often above 2,000 mm annually) in the Northeast dilutes pollutants, and thick forest cover acts as a natural filter. For instance, Mizoram’s 92.5 WQI reflects largely unpolluted rivers like the Tlawng, aided by low population density (around 52 people per sq km) and limited large-scale industry.

Bottom 10 States with Poorest Water Quality (2025)

Highly urbanised and industrial regions with large population concentrations cluster at the lower end.

The WQI of 50 in Delhi reflects a severe urban water crisis: about 3,000 MLD of untreated sewage from 22 drains flows into the Yamuna, pushing dissolved oxygen below 2 mg/L and BOD above 30 mg/L in stretches levels unfit even for bathing. Uttar Pradesh records a score of 55, reflecting chronic pollution of the Ganga from tanneries and urban centres, while Rajasthan gets a score of 66 because of arid conditions, heavy groundwater extraction, and low sewage treatment-slightly over 30% of 1,200 MLD wastewater is treated.

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Key Patterns Behind the Rankings

1. Geography and Rainfall

High rainfall, forest cover, and low density naturally help the Northeast and Himalayan states maintain better water quality.

Places with arid conditions, such as Rajasthan, have situations where salts and nitrates are concentrated due to the effect of over-extraction and increased evaporation that intensifies contamination.

Islands present mixed results wherein Lakshadweep scores 80 due to flushing by lagoons, while Andaman & Nicobar present a score of 79.5.

2. Industrial and Agricultural Pressures

Maharashtra's 58.5 reflects sewage and industrial effluents around Mumbai; CPCB lists 45 polluted stretches in the Godavari and Tapi with chromium beyond safe limits.

The stretches of Ganga in Uttar Pradesh receive extremely high fecal coliform loads-from tanneries and urban discharges-up to a level of 10⁶ MPN/100 mL.

Undoubtedly, excessive use of fertilizer in districts of Punjab (65) and Haryana (64) fosters nitrate pollution and depletion of groundwater, which is accentuating eutrophication in rivers like the Sutlej.

3. Urbanization and Population Density

The 22 million residents of Delhi produce some 800 million gallons of wastewater daily, which overwhelms sewage treatment plants running at roughly 70 percent capacity.

Fast-growing hubs like Gurgaon add industrial waste to already stressed rivers and drag down the WQI of Haryana.

By contrast, Goa has more rigid tourism and environmental control, maintaining the dissolved oxygen level at greater than 5 mg/L in Mandovi.

4. Governance, Sanitation and Treatment Capacity

States like Kerala (85), Telangana (74), Gujarat (63) and Odisha (73) point to how certain investments in sewage treatment and river-cleanup projects raise WQI scores.

Odisha's improvement is attributed to 50 new treatment plants since 2022, reducing pollution in the Mahanadi by around 15%.

A lowly rank of 68, Bihar showcases weak rural sanitation: nearly 90% of its villages lack proper facilities, leading to 500 MLD untreated sewage entering Ganga tributaries and high coliform counts.

Government Initiatives and Future Outlook

Flagship programs are gradually causing a shift in trajectory, but face scale and climate challenges.

• Namami Gange: The State outlay of ₹ 30,000 crore provides for the rejuvenation of 350 river stretches of the Ganga, from 45 in 2018 to approximately 60 in 2025, and will have a huge multiplier impact in Uttar Pradesh.

• Atal Bhujal Yojana: Implemented in seven over-exploited states, including Rajasthan, with a focus on groundwater recharge and possible WQI gains of 5–8 points by 2030.

• Jal Jeevan Mission & Swachh Bharat: For the expansion of piped water and rural sanitation, for example, progress in Chhattisgarh to a WQI of 72, helps reduce open defecation and sewage inflows into local rivers.

Yet, climate change threatens to undo these gains: projections linked to the IPCC of a 20 percent reduction in Himalayan flows by 2050 might undermine the strong current showing of states such as Uttarakhand (82). Megacities like Delhi will also require massive capital investment-estimated at ₹10,000 crore for full Yamuna rejuvenation-to climb out of the "poor quality" bracket.

Overall, the 2025 WQI rankings make clear that cleaner water is achievable where proactive treatment, regulation, and community management are in place-but also that without urgent expansion of sewage and effluent treatment, industrial belts and dense urban corridors will continue to lag behind.

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