Hindustan Motors has decided to take environment pollution by its horns and has launched a massive campaign to promote its CNG-driven Ambassadors. To begin with, HM is offering two CNG models - the Ambassador 1500(runs only on CNG) with a price tag of Rs 3,15,558 and the Ambassador 1800 ISZ bi-fuel(which runs on both CNG and petrol) with price tags ranging from Rs 3,72,943(non A/c) and Rs 4,18,449(A/C).