Why is pistachio not grown in India and can I try it anywhere?

Pistachio is severely climate restricted and is essentially not a commercial crop in mainland India. It needs hot dry summers plus a real cold winter with enough chilling hours, the kind of continental climate found in Iran, parts of the USA and some Central Asian regions. Most of India is either too humid, too hot without winter chilling, or both, so the trees may grow but rarely set good commercial nuts. At best some experimental planting has been tried in very high cold dry pockets like parts of the cold desert region, with no established commercial success. It is also a long gestation, slow bearing tree. Honestly, for almost all Indian farmers pistachio is not a viable crop, and you should be very cautious of any nursery selling pistachio plants with big income promises. Confirm with a horticulture university before spending money.