NEW DELHI: Leader of Opposition in Delhi Assembly V. K. Malhotra has expressed concern at recent incidents of fire in some of the newly-commissioned low-floor buses, saying they have become a cause for alarm even as the terror of Blueline buses persists as they are yet to be phased out completely. Prof. Malhotra said these expensive green buses were integrated into the Delhi Transport Corporation fleet by the Sheila Dikshit Government amid much fanfare but the fire incidents have put a big question mark over their safety. Maintenance cost The senior BJP leader noted that the cost of maintaining these buses was more than their purchase cost.