Quantification of annual methane emissions from landfills in India using satellite retrievals

Abstract

Landfills in India are a growing environmental concern, emitting large amounts of methane (CH4) that affect the climate and local air quality. However, observational and modelling studies quantifying CH4 emissions from landfills in India are sparse. Although satellites are being widely used globally to estimate CH4 emissions from landfills, studies focused on India are limited. Here, we use the blended column CH4 (XCH4) data derived from the TROPOMI and GOSAT satellites to estimate annual-mean CH4 emissions at four Indian landfill sites (Bhalswa, Ghazipur, and Okhla in Delhi and Ahmedabad in Gujarat) for the period 2019–2024. Multi-year mean (2019–2024) emissions range from 24 Gg a−1 at Bhalswa to 87 Gg a−1 at Ghazipur, with the three Delhi landfills collectively emitting approximately 200 Gg a−1 in 2024. Ghazipur exhibits the strongest increasing trend, with emissions nearly doubling from 61 Gg a−1 in 2019 to 120 Gg a−1 in 2024. The satellite-based CH4 emission estimates for 2024 are higher by 70%–90% at Ghazipur and Okhla, and by 30%–70% at the Bhalswa landfill sites, compared with model-simulated values reported in the existing literature. This study highlights the effectiveness of the utilisation of satellite-based XCH4 retrievals to improve annual-mean methane emission estimates from point sources in a country with limited observational data, to support the targeted emission mitigation efforts.