Singh yesterday asked field officers to ask contractor companies to strictly adhere to the terms and conditions, saying "no violation will be tolerated in this regard", the spokesman said.
"Keep a close check against dumping of muck in forest land, water bodies and other areas that may disturb the ecosystem," the minister said.
He was inspecting the four-laning work on the highway, the only all-weather surface link connecting Kashmir with the rest of the country.
Singh exhorted the officers to restore degraded forest areas along the national highway and also directed them to keep close vigil on "illegal activities" in forest area, he said.
The forest minister also chaired a high-level meeting of officers of the department and laid foundation stone of Forest Hut at Patnitop, the spokesman added.