Compressed biogas, a sustainable solution to Delhi’s pollution crisis

Setting up of compressed biogas (CBG) plants that use paddy straw as a feedstock could reduce winter pollution in Delhi by around 30%, reveals a study by Nomura Research. A single CBG plant producing 10 tons per day can significantly reduce particulate matter emissions, equivalent to replacing numerous petrol cars with electric vehicles.

Delhi’s pollution crisis requires a shift in agricultural waste management, with compressed biogas (CBG) offering a sustainable solution to address both stubble burning and vehicular emissions, according to a report by Nomura Research Institute Consulting & Solutions India. CBG, as a renewable fuel, can replace fossil-based CNG and PNG in transportation, industry, and households, offering significant benefits beyond just pollution reduction, the report noted.

The city’s toxic air is caused by a range of sources, including vehicle emissions, construction dust, biomass burning (including paddy straw stubble burning), and industrial emissions. The report highlighted that while vehicles contribute 20% to Delhi’s pollution in summer and stubble burning 16%, these figures rise to 30% and 23% respectively, in winter. During peak stubble-burning season, emissions from biomass can exceed 30%.

“A CBG plant producing 10 tons of CBG per day requires about 90 tons of paddy straw. By repurposing this biomass instead of burning it, we can prevent about 270 kilograms of PM (particulate matter) emissions every single day,” the report stated. A 10-ton-per-day CBG plant could eliminate 11,000 to 12,000 kg of PM emissions annually, equivalent to removing 1.5-1.75 lakh petrol cars or 25,000 older, high-polluting vehicles from the roads, the report noted.

For CBG adoption to be effective and sustainable, the report emphasizes the need for coordinated efforts between the government, private sector, and farmers. A combined approach with demand-side and supply-side measures is crucial. 

On the supply side, policy incentives, infrastructure development, and financial support are necessary to scale up CBG production. On the demand side, mandatory blending policies, penalties, and incentives for industries and the transport sector are needed to encourage the use of CBG as a cleaner alternative to fossil fuels.

Starting in 2025-26, the Union Petroleum Ministry will mandate CBG blending, requiring CGD (city gas distribution) entities to procure and distribute CBG under the CBG-CGD synchronization scheme. The blending targets are set at 1% for FY26, 3% for FY27, 4% for FY28, and 5% from FY29 onwards. However, no penalties will be imposed for non-compliance.