West Bengal gets 84 per cent of its thermal power from coal-based plants that are yet to comply with sulphur dioxide emission norms notified by the Environment Ministry, the maximum by any state in the country, according to a study conducted by the Centre for Science and Environment (CSE).
Telangana (74 per cent) and Gujarat (71 per cent) are also among the nine major defaulting states.
On an average, 33 states and Union territories in the country receive 58 per cent thermal power from "unclean" coal-fired power plants, it said.
In its assessment, the CSE ranked the states and Union territories (UTs) based on how much electricity they get from "unclean" coal-fired power plants.
"'Unclean' coal-fired power plants are those which have not made any progress to comply with the emission norms so far. Those who have awarded work to meet the standards have been considered under the ''cleaner'' coal-fired stations," Soundaram Ramanathan, deputy programme manager, industrial pollution unit, CSE, said.
The ministry had notified emission norms for particulate matter, sulphur dioxide and oxides of nitrogen in 2015. These had to be complied with by power stations in 2017.
Nine states -- West Bengal, Telangana, Gujarat, Rajasthan, Andhra Pradesh, Uttar Pradesh, Maharashtra, Chhattisgarh, and Tamil Nadu -- are the major defaulters as per the study.
On an average, these states have been procuring around 60 per cent of their thermal power from "unclean" coal-fired stations, the CSE report said.
Nivit Kumar Yadav, programme director, industrial pollution, CSE, said, "Coal-fired power stations emit three major pollutants -- particulate matter, oxides of nitrogen, and sulphur dioxide. Power stations have been specially lagging behind in their compliance with the sulphur dioxide norms."
"Therefore, in this study, the researchers have considered the progress made by stations to meet the sulphur dioxide norm as a measuring scale to identify the 'dirtiest' power," he said.
The study comes at a time when the Ministry of Power is "pushing the Ministry of Environment, Forest, and Climate Change to dilute or further delay the implementation of sulphur dioxide norms", Mr Ramanathan claimed.
India's present installed power capacity (till November 30, 2020) is 374 gigawatts (GW). Of this, coal and lignite account for 205.8 GW (55 per cent).
Renewable sources of energy, including solar, wind, and biomass, contribute about 90 GW.
"Of around 162 GW of coal power capacity, for which data is available on the website of the Ministry of Power, 58 percent on an average comes from ''unclean'' coal-based power plants," Mr Ramanathan said.
According to the study, in West Bengal, 84 per cent of the thermal power comes from "unclean" coal-based power plants far away from meeting the sulphur dioxide norms.
In Telangana, this figure is 74 per cent. It is 71 per cent in Gujarat.
The study also found that in three of the nine states -- Rajasthan, Andhra Pradesh, and Tamil Nadu -- "unclean" power stations were one of the key sources of ambient air pollution in non-attainment cities.
In the remaining three states -- Maharashtra, Chhattisgarh, and Uttar Pradesh -- "unclean" power stations are located in clusters, and are not making sufficient efforts to comply with the norms, it said.
"Only 13 states/UTs (out of 33) are sourcing 100 percent of their requirements from clean coal-based power stations. These are Arunachal Pradesh, Assam, Chandigarh, Daman & Diu, Himachal Pradesh, Jammu and Kashmir, Jharkhand, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura," the CSE said.
Delhi and Goa are also very close in terms of procuring the clean power -- only 5-8 per cent of their electricity comes from unclean sources.
Of the nine states buying maximum unclean power, only Gujarat and West Bengal have the full authority to monitor the stations as these are located within their state boundaries.
The rest of the states have dual accountability of cleaning up both their own stations as well as ensuring stations supplying to them from other states are clean.