Delhi: The 2010 Auto Expo had at least seven efficient 'green' passenger cars out on stage. But the eco-friendly cars won't be seen in India anytime soon due to a range of infrastructure issues. Here are the challenges that each class will face in India.

CNG CARS

* Inadequate refuelling stations across cities.
* Bulky CNG kits often eat into boot space of cars.

HYBRID VEHICLES