Moreover, the undertaking is also looking at the feasibility of introducing air-conditioned double-decker buses, said BEST committee chairman Pravin Chheda. "We are set to introduce around 50 new double-deckers that run on Compressed Natural Gas (CNG).

The new buses will be here by May," Chheda said."Gradually, we also plan to phase out the old diesel-fuelled doubledeckers."

Most of the existing ones are nearing the 15-year age-limit set by a Bombay High Court directive dated December 19, 2003. The transport body's 171 double-deckers are mostly plied along short distance routes to cut down operating costs. Since these vehicles run on diesel, they are considered "economically unviable". Also, according to BEST officials, a doubledecker requires two conductors and operating costs therefore rise to Rs 54 per km as compared to Rs 37 per km for a single-decker BEST bus that runs on diesel.

Owing to these reasons, last year, the undertaking had planned to downsize the ubiquitous red double-decker fleet as it was unviable to run them for the loss making transport body. Chheda, a committee member then, says he opposed the idea. "BEST first launched the double-deckers in the city in 1937. Over the years, the red double-decker has become an integral part of the city's landscape. It cannot be scrapped," Chheda said.

Meanwhile, the undertaking has asked a few automobile manufacturing companies to prepare and submit a design for air-conditioned double-decker buses.

"We would like to introduce air-conditioned double-decker buses too and for this we have asked for new designs for such buses," Chheda added.