Section 2(1)(a) in THE COMMISSION FOR AIR QUALITY MANAGEMENT IN NATIONAL CAPITAL REGION AND ADJOINING AREAS ACT, 2021
(a)“adjoining areas” means the areas in the States of Haryana, Punjab, Rajasthan and Uttar Pradesh, adjoining the National Capital Territory of Delhi and the National Capital Region, where any source of pollution is located, causing adverse impact on air quality in the National Capital Region;