Report to SC finds Delhi’s WTE plants mostly within standards
New Delhi: Delhi’s all four waste-to-energy (WTE) plants, long at the centre of public concern, located at Okhla, Ghazipur, Bawana, and Tehkhand, are broadly following regulatory standards and do not present any major threat to public health or the environment, a joint review by the Central Pollution Control Board (CPCB) and the Delhi Pollution Control Committee (DPCC) has found.
The assessment, submitted before the Supreme Court and the National Green Tribunal, highlights that each facility is equipped with pre-processing systems that raise the calorific value of municipal waste above 1,500 kilocalories per kilogram, as required under the Solid Waste Management Rules, 2016. Emission testing shows that suspended particulate matter and heavy metals like nickel remain within permissible limits.
However, the Bawana facility recorded higher-than-allowed levels of dioxins, furans, cadmium, and thallium. Even so, the report underlined that the potential cancer risk linked to these emissions remains far below the risk levels recognised by the United States Environmental Protection Agency.
Ambient air quality checks at eight monitoring stations near the plants showed occasional spikes in PM10 and PM2.5, but these were similar to readings recorded across Delhi’s larger monitoring network. Elevated ozone and nickel were also observed in some locations. The report clarified that nickel readings were taken over 24 hours and therefore not comparable with long-term averages, adding that the WTE plants contribute only minimally to such pollutants. Additional monitoring for nickel has been recommended at Ghazipur and Bawana.
On waste handling, bottom ash at three plants was found compliant, while fly ash at Bawana exceeded limits for cadmium, lead, manganese, and copper. In wastewater discharge, Bawana’s treated effluent showed excess biochemical oxygen demand, Ghazipur recorded higher levels of dissolved solids and chlorides, and Tehkhand reported elevated chlorides and phenolic compounds. Groundwater samples showed cadmium, copper, and lead within safe limits, though iron exceeded standards in Bawana and Ghazipur. Broader tests detected hardness, sulphates, nitrates, and phenolic compounds above norms at Bawana, Ghazipur, and Tehkhand.
The modelling of ground-level pollution concentrations suggested extremely low values, well below national standards. Following the review, CPCB directed all WTE facilities to install real-time continuous emission and effluent monitoring systems within three months. Draft guidelines on municipal solid waste incineration have also been released for public feedback.
The findings come as courts increase scrutiny of Delhi’s waste management. Earlier this year, the Supreme Court stressed the importance of segregation at source and directed CPCB to assess the environmental performance of WTE projects. In July, the Environment Ministry cleared a new 30 MW WTE project at Bawana despite opposition from residents, who raised concerns about pollution impacts similar to those near the Okhla plant. The apex court has now asked CPCB to evaluate the project’s likely effects on health and the environment.
