The green panel also issued notices to the governments of Delhi and Haryana on the plea which claimed that there was an erosion of the mandatory green cover on both sides of NH-1 and NH-8 which was necessary to maintain the ecological balance between pollution and development.
A bench headed by NGT chairperson Swatanter Kumar asked the respondents to file their reply and fixed the matter for hearing on September 7.
"As per norms adopted by the NHAI, mandatory green of 30 metres on each side of the highway/scheduled road and 50 metres on both sides of any bypass is to be maintained," it said.
It claimed that effective green cover along the national highways have manifold uses and NHAI itself has prescribed the mandatory green cover.
"This is a huge loss to the green cover of the country, which is struggling with acute shortage of water and is faced with humungous air and noise pollution," it said.
"The basic concept is that trees should be planted along the highway to maintain ecological balance between pollution and development and the future need for expansion of roads and insulate the population living nearby from noise pollution, dust and emission pollution," it said.
It sought a direction to authorities concerned for declogging of traffic on national highways.