Yes, you can get your Toyota Corolla Altis LPG fitted approved by the Govt.Of India. For the availability and all related details, visit your nearest Toyota service centre as they will be able to assist your better for the same. Click on the link to find the nearest Toyota service centre https://www.cardekho.com/Toyota/cardealers
Yes you can get it installed. But we won't recommend it . Since, it will void warranty. CNG is best suited alternate fuel option instead of LPG. However, there are no CNG filling stations available in Faizabad UP. The nearest one is in Lucknow.
We would not recommend a CNG kit on Brio for it doesn't have a lot of low end torque in the first place and the kit makes it worse. On CNG, it will require a lot of throttle input to get it going in the first and second gear. Hence, we would not recommend you to get CNG kit fitted..