The Delhi government plans to file an appeal before the Supreme Court seeking sanction for another two years to phase out the old Delhi transport Corporation (DTC) buses running on eight-year-old diesel engines. The Supreme Court had set the deadline of March 31, 2000 for the Delhi government to either phase out these old vehicles or replace them with compressed natural gas (CNG) engines. A section of the State Transport Authority (STA) are of the view that failure to implement the court orders and meet the deadline stems from the government failure to take up the CNG scheme in right earnest.