When two such plants in Narela and Ghazipur are about to start operations, experts at a conference organized by Toxics Link, an environmental NGO, said incineration plants are expensive, yet unviable. There is a consensus that mixed trash is unsuitable for incineration, as it's not only polluting but extremely inefficient due to its low calorific value.

Shyamala Mani, professor at National Institute of Urban Affairs (NIUA), that assists the ministry of urban development in formulating policies, highlighted concerns with the quality of waste in cities. She quoted a recent study by National Environmental Engineering Research Institute (NEERI) and Central Pollution Control Board (CPCB) that measured the emissions from a landfill site called Dhapa near Kolkata and found very high levels of non-methane volatile organic compounds including several carcinogens. Since the composition of waste in cities is similar, the findings apply to Delhi's poorly managed landfill sites and mixed waste as well. The study concluded that the cumulative cancer risk was found to be 2,792 per million population. Workers at landfill sites are at major risk.

NIUA has made formal representations to the ministry of environment, forests and climate change and CPCB requesting a policy to be drafted for handling of hazardous waste from homes and small industries. "Mercury in Indian waste is 10 to 15 times the prescribed standard. Unless MoEFCC supports us with a detailed description of how these can be handled, we are skeptical," she said referring to plans for more waste-to-energy plants. She also highlighted that the calorific value of mixed waste is about 50% lower than what's required for incineration. This leads to less energy being generated. Pollution control measures for these plants are also expensive.

There was intense debate about the waste-to-energy plant in Okhla over the same concerns. Residents from the area alleged that plastics and other hazardous waste are routinely incinerated by the plant putting their very lives at risk. Dieter Mutz, director of GIZ, too, said that the plant had been incinerating all kinds of waste including valuable reusable material in construction and demolition waste. Speakers also highlighted that the technology is very costly, the Okhla plant cost about Rs 200 crore and was developed in a public-private partnership model.

Saurabh Khatri of Delhi Dialogues Commission, a thinktank under the new AAP government, asked experts if segregating waste in Delhi can help address the problem. DDC is likely to hold a stakeholders' meet with civil society organizations and waste workers on waste-to-energy early next month.

Industry bodies, however, tried to justify incineration. "Incineration can be done in a small space whereas biomethanation requires a huge amount of space that Delhi doesn't have. Now it's up to the government," said Gyan Misra of IL & FS, that's setting up plants in Ghazipur and Timarpur. CPCB scientist Vinod Babu, too, claimed that the issue of dioxin release in Okhla plant has been addressed and the plant is functioning properly.