delhi has been a part of various governments
 see also delhi metropolitan arealist of people from delhilist of twin towns and sister cities in india explanatory notes  references  further reading  external links  governmentofficial website official tourism sitegeneral informationdelhi web resources provided by govpubs at the university of colorado boulder librariesdelhi at the encyclopdia britannicadelhi at curlie wikimedia atlas of delhi geographic data related to delhi at openstreetmap
 since the mid1990s delhi has undertaken some measures to curb air pollutiondelhi has the thirdhighest quantity of trees among indian cities and the delhi transport corporation operates the worlds largest fleet of environmentally friendly compressed natural gas cng buses