Nearest CNG station is around 52 kms away from Lonavala in Pimpri Chinchwad. Address for the same and another nearest station is as follows:
Petrol and CNG station
Address: Mumbai Pune Highway, Pimpri, Pimpri Chinchwad, Maharashtra
Bharat Petroleum CNG fueling station
Address: Palm Beach Road, Sector 20, Belapur, Navi Mumbai
Also, there are few others around Navi Mumbai and Pune.