As we near this year's closure, Delhi continues to retain its dubious distinction as the country's capital with the poorest air quality, as in the past several years. Despite mitigation efforts and the Court’s interventions, the fight against pollution remains unsuccessful. This year, the Air Quality Index (AQI) often reached the upper limit of the worst category, a condition comparable to living in a gas chamber.
Several scientific organisations, including the Indian Institutes of Technology, sleuthed why the worsening air pollution enveloped the capital city during winter. The causes of the world’s worst-quality air that Delhi residents frequently breathe mostly originate from human activities – burning coal, petrol, diesel, gas, biomass in industries and coal-based power plants. Contributions from kitchen smoke, vehicular emissions, large-scale construction activity, firecrackers and burning residual crops also vitiate the air. A temperature inversion also characterises the winter months, and heavier wind traps pollutants closer to the ground and prevents them from dispersing.
Other than toxic gases like sulphur dioxide, ground-level ozone, carbon monoxide, and nitrogen dioxide, particulate matter forms the major pollutants, including dust particles, fly ash and toxic liquid droplets. Particulate matter (PM) is categorised into micro-meter sizes PM10 and PM2.5. Because of its microscopic size, the latter-mentioned particulate matter that can reside deep in the lungs is a serious health risk.
For the last few years, Delhi has recorded an annual average PM2.5 concentration of more than ten times the acceptable value of WHO's air quality guideline. Particulate Matter PM2.5 can lodge deep in the lungs, causing respiratory illnesses, and children are found to be victims of long-term effects. Air toxicity also results in increased incidences of cancer and miscarriages.
Over the last few months, Delhi air pollution has become a topic of discussion in the media, and the authors of the articles mainly suggested three solutions for clean air in Delhi: crop diversification in the neighbouring states and a major transformation in the transport sector to switch to electric vehicles and introduction of innovative technologies.
For whatever reason, only a few like the Centre for Research on Energy and Clean Air (CREA) turn the spotlight on thermal plants which emit sulphur dioxide emissions at levels 240 times higher than stubble burning, that too throughout the year. The report says, "While stubble burning receives heavy penalties, coal-fired power plants operate with repeated compliance extensions”.
The fact is that India's coal-based power plants can reduce their annual sulphur dioxide emissions from the exhaust of the plants by more than 60 per cent by installing flue-gas desulfurisation systems. The coal plants are not amenable to the guidelines from the Ministry of Environment, Forest and Climate Change; the Union Power Ministry has been seeking extensions of deadlines. Seven years after the issuance of guidelines, the Central Electricity Authority has now missed two deadlines and asked for time till 2035. This must be part of the strategy that all such power plants will reach their retirement by 2035, and thus, the plant owners can escape the huge financial investment.
Besides the coal power plants, which are major perpetrators of environmental crime, Delhi’s four waste-to-energy (WtE) plants located in Ghazipur, Narela, Okla and Tehkhand have now attracted global attention. The plants burn waste to produce steam that runs turbines to generate electricity as a solution to the mounting garbage. While the WtE plants in Delhi generate electricity, they produce two types of ash: bottom ash and fly ash. What remains after combustion is bottom ash, which comprises about 20-30% of the original waste volume. Delhi's waste-to-energy incinerators have long been hailed as a green solution to the city's mounting garbage crisis. These facilities have now become an open pit garbage fire billowing chemically toxic particulate matter and gases.
Focusing on the Okla plant commissioned in 2012, The New York Times published a startling investigative report on November 9, 2024, exposing the alarming health and environmental impacts. The fly ash from the plant’s neighbourhood was found to contain cadmium, four times higher than the EPA permissible limits, ten times the number of dioxins than allowed – another notorious toxic substance that the USA used during the Vietnam War.
Both types of ash require careful handling and disposal in scientifically managed landfills to prevent environmental contamination. The WtE process involves collecting and transporting waste to the plants and sorting to remove recyclables and hazardous materials, finally feeding the sorted-out waste into the incinerator. It is now reported that the plants violate ecological norms in handling the fly ash, causing air contamination and polluting the groundwater near the dump yards because of its heavy metal content.
Despite the public concerns over health and environmental impacts, no clear guidelines under the Graded Response Action Plan (GRAP), have been issued against the WtE plants applicable for power plants, industrial plants, hot-mix plants and brick kilns. To promote research for fly ash utilisation, a technology project, Fly Ash Mission, was started in 1994 and was amended in 2003, 2009, and 2016.
Early this year, the Power Ministry launched a web-based monitoring system to manage better utilisation of fly ash by providing an interface between fly ash producers and potential users such as road contractors and cement plants. It is also used to manufacture bricks, blocks, tiles, etc., saving the fertile top layer of soil. Although some states like Punjab make good use of fly ash in the cement industry and road construction, the utilisation percentage of many states, including Uttar Pradesh is around 45%.
These plants use old methods of WtE generation. It is unclear if they use any types of filters or scrubbers which prevent acid from reaching the atmosphere and capture the pollutants. Modern incinerators incorporate carefully engineered primary and secondary burn chambers and controlled burners designed to burn completely with the lowest possible emissions The newest such plants elsewhere in the world use stoker technology, and others use the advanced oxygen enrichment technology. Several treatment plants exist worldwide using relatively novel processes such as direct smelting.
The precautionary principle was defined at the Wingspread Conference in 1998 as, ′When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically,’ highlighting the principle as a foundational tenet of the environmental justice movement. It is time to reevaluate the efficacy and usefulness of WtE plants in Delhi as a green solution to the garbage problem and stop its current functioning.
(Disclaimer: The opinions expressed in this article are those of the writer. The facts and opinions expressed here do not reflect the views of ETV Bharat)
