Concerned over a spurt in fires aboard CNG buses, the transport department of Delhi Government is now tightening its noose around bus operators evading the mandatory CNG-kit test. Following the special enforcement drive ordered by Delhi Government, the transport department has impounded over 300 privately owned vehicles including Blueline buses that were running on the roads without a valid fitness test. A total of 1,900 commercial vehicles including 500 Blueline buses in the Capital have failed to get the CNG leak-proof certificate. The operators have been asked to produce the certificate by December 18, failing which their permits would be cancelled. Delhi Transport Minister Arvinder Singh Lovely said that a special drive has been started against all commercial vehicles to check their documents. Nearly a dozen mobile teams from the transport department