Gurugram, Feb. 14 -- The National Green Tribunal (NGT) has asked the Haryana government to investigate possible collusion of officials of the state pollution control board and the department of town and country planning (DTCP) with the developer of Sushant Lok-1, which was built without environmental clearance. The project violated several norms - not providing rainwater harvesting system, extracting groundwater illegally, discharging sewage in stormwater drain and operating diesel generator sets without any safeguard, the NGT said....