Not sure what they use in Delhi, but here in Korea we actually have rangers who shoot blank rounds at birds to chase them away at airports. See first photo in

Not sure what they use in Delhi, but here in Korea we actually have rangers who shoot blank rounds at birds to chase them away at airports. See first photo in https://www.yna.co.kr/view/AKR20230307131700056 https://www.yna.co.kr/view/AKR20230307131700056 (article in Korean) The machine in the second photo looks like a cannon but actually sprays insecticide. The goal is to remove insects that the birds feed on, giving them less reason to approach the area in the first place. Due to the proximity of most Korean airports to residential areas and important military targets, an automated cannon that makes explosive sounds at random would be a big no-no. People would think the airport was being bombarded, or more likely, the President had declared martial law again :(