Compressed natural gas, a luxury of Delhi and Mumbai, will now be available in other cities as well. Aptly code-named 'Operation Blue Sky' by the Gas Authority of India (GAIL), the proposed national gas grid will initially make CNG available to four more cities - Kanpur, Lucknow, Hyderabad, Faridabad. The move is in keeping with the Supreme Court's April 2002 ruling to provide unadulterated fuel in critically polluted cities - Kanpur, Lucknow, Bangalore, Ahmedabad, Hyderabad, Chennai and Solapur. The availability of CNG in other cities for transport will have a direct bearing on air quality, environmentalist said. "The issue is similar to what we have focussed in Delhi. Because emissions standards are so lax, for vehicle technology and fuel, it makes this kind of fuel-based approach more viable," said Anumita Roychoudhury, Centre for Science and Environment.