Why are compressed natural gas buses used in Delhi?

Compressed natural gas (CNG) buses are utilized in Delhi primarily as a strategic measure to combat the city's severe air quality issues.

Urban air pollution in major Indian cities like Delhi is significantly exacerbated by vehicle emissions, which account for approximately 20–30 percent of the total urban pollution. Exhaust from traditional vehicles releases toxic carbon monoxide and unprocessed hydrocarbons, which contribute to the formation of smog and pose serious health risks, including respiratory problems. Furthermore, vehicle exhaust is a major source of PM${}_{2.5}$ particulate matter, which remains a critical concern for Delhi's air quality.1

By transitioning a significant portion of the Delhi Transport Corporation's fleet to natural gas, the city aims to reduce these harmful emissions. This initiative is part of a broader effort to manage the environmental impact of the city's overburdened transportation network and rapid population growth.21