More than 600 kilometres of cycle tracks have been developed in 100 smart cities while over 76,000 CCTV surveillance cameras installed so far, the Union Housing and Urban Affairs Ministry said on Thursday. Under the Smart Cities Mission, 6,855 “smart classrooms” and 40 digital libraries have been developed. Also, over 50 lakh solar and LED streetlights have been installed and over 89,000 km of underground electricity cabling constructed, it said.