From 519 in 1976, count has dropped to 251 now, while 4 main reservoirs have shrunk due to encroachment
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/how-half-gurugram%E2%80%99s-water-bodies-vanished-40-years
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-gurgaon
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/haryana
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/gurgaon-t
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-resources
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/land-encroachments
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/panchayats
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-groundwater-board-cgwb
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/groundwater