9,294 /km 2 (24,071 /sq mi) • 18405858 Ethnic groups     [show] Religious: Hinduism Muslim Sikh Jain Christian Parsi Buddhist Jew Linguistic: Punjabi Haryanvi Urdu Bihari Bengali Tamil Rajasthani Telugu Garhwali Kannada Malayali North-East Marathi Gujarati Time zone IST ( UTC+05:30 ) Area • Elevation 42.7 km 2  (16 sq mi) • 216 m (709 ft) Codes [show] •