Tata Motors recently introduced its new twin-cylinder CNG setup in the Tiago hatchback and the Tigor sedan. These models have already been launched, with the Tiago CNG priced at Rs. 6.55 lakh and the Tigor CNG costing Rs. 7.80 lakh (ex-showroom). The carmaker now has four models in its CNG line-up with this new twin-cylinder technology, including the Altroz and Punch. Here's what's new in the Tiago and Tigor CNG vehicles.