India’s environment tribunal, the National Green Tribunal (NGT), on Tuesday directed the Airports Authority of India (AAI) and the Delhi International Airport Limited (DIAL) to implement measures authorized by it in a 2017 decision. The order aims to curb noise pollution in India’s capital New Delhi.

NGT Chairperson Adarsh Kumar Goel and two other judicial members, Judge SP Wangdi, and Judge K Ramakrishnan, pronounced the decision in a bid to reduce noise pollution in the vicinity of New Delhi’s Indira Gandhi International (IGI) airport.

The bench ordered the government to “take all mitigating measures for reducing noise pollution…expeditiously.” According to the order, the measures include “construction of sound barriers” around the airport “at the earliest.” The government has also been directed to provide for “a green belt around the boundary wall of the airport while keeping the safety and security both in mind. The plantations shall be of the species that would only grow to the permissible height or would be maintained at the permissible height only.”

Relevant authorities such as the AAI are to issue instructions to airlines “whose aircraft land at the runway of the IGI airport to ensure judgment-based use of reverse thrust keeping in view weather, length of the runway, wind, and other attendant circumstances to reduce the noise level particularly at the time of landing of aircraft.” The measures are not limited to structures around the airport or the aircraft. Public transport used at the airport is also expected to adhere to environmental norms. “All the coaches/buses and other vehicles plying at the airport should be Compressed Natural Gas (CNG) and must comply with the prescribed emission standards. Non-CNG buses/coaches or other vehicles plying at the airport should be converted to CNG,” the order reads.