Hybrids are a great idea, and if coupled with CNG, the hybrid will be even more economical. It uses two engines side by side, Electric engine (for initial torque for the speeds between 0-30 or 35 miles ) and switches to Gasoline (Petrol) engine automatically for speeds greater than 30 to 35+ miles. The Gasoline engine is usually small 4 cylinder of 1000cc, it can be run on CNG. The Electric engine runs on batteries. The batteries get charged by the generators coupled with gasoline engine. Plus these cars also recharge while braking, the electric generators are turned and slow the car, (re-generative braking). So when you brake the car, the actuators on the brakes transfer the brake's toque power to turn the electric generators. So you never need to recharge the electric batteries of the car.
The cost of the car is heavily subsidized by the Manufacturers, since this is a very new technology and initially any new technology takes time before it turns profitable. Sine the makers of these cars, mainly Toyota (Prius), Honda (Insight) are paying out of their pockets to martket these cars, these are affordable. The Toyota Prius is around $17,000 to 18,000 ( ir roughly 10 lakh rupees) cheaper than Toyota Corolla or Honda Civic in Pakistan. These should be marketed in Pakistan, and eventually assembled, manufactured. Pakistan is in learning stages of Auto Industry, why not get a head start on the new technology.