a larger chequered grille and square park lamps. Now separate amber indicator lamps were incorporated on the semi front lip spoiler below the bumper which was mounted higher up. This model was named as the Mark IV. In addition to the existing petrol version, a diesel variant was launched in 1980, powered by a 1489 cc, 37 bhp BMC B-series diesel engine. It was the first diesel car in India and was well received by the Indians, although it was initially only available as a taxi or for government usage, as the Indian government restricted private ownership of diesel automobiles. It was, at the time, the most expensive car built in India, at a 25 percent markup over a petrol Mark 4. The Mark IV was the last of the Mark cars. For a short period the cars were available as Deluxe and later it was renamed Ambassador Nova. The Ambassador of 1990 (except for the front cowl area) was virtually identical to the 1956 original, with most changes being light and cosmetic. The changes were mainly the front styling and minor changes to the dashboard. This technological stagnation was mainly because of the protectionist policies being pursued by the Indian government at the time, and there was little incentive on the part of Indian companies to innovate. During that time, the newly Hindustan Contessa started getting produced, intended to replace the Ambassador, however, the Ambassador proved to be more popular, and so surpassed the Contessa in production. The car celebrated the Golden Jubilee of its production in 2008 (1958–2008). The Ambassador has emerged as the car mass-produced for the longest period, with minimal design changes, on the same assembly line (Uttarpara, West Bengal, India) in the whole world until 2014. It was during the Mark IV's model run that India launched a controlled economic liberalisation in the mid-1980s which allowed many Japanese companies to establish joint ventures in India. Maruti Suzuki launched its Maruti 800 in the then non-existing small car category. The then existing manufacturers Standard Motors, Premier Automobiles and Hindustan Motors were licensed for larger category cars. The Ambassador still remained the principal family car of choice in the middle segment in spite being a pre-modern design with dated styling. The company also earmarked for a major upgrade for its mechanical and power plant systems, creating a model later launched as Nova. Ambassador Nova The Ambassador Nova