Kimi Raikkonen hung on to third place in the overall standings with seventh place for Lotus but he is now 67 points off the lead and just six ahead of Webber.
McLaren's Lewis Hamilton and Jenson Button finished fourth and fifth respectively, with the latter denying Vettel the fastest lap but with his title hopes now mathematically over for another year.
Brazilian Felipe Massa was sixth for Ferrari, ahead of 2007 champion Raikkonen, with Germany's Nico Hulkenberg eighth for Force India in the team's home race.
Frenchman Romain Grosjean finished ninth for Lotus and Brazilian Bruno Senna grabbed the final point for Williams on an afternoon short on thrills for the crowd making the trip south from New Delhi.
In Image: Ferrari driver Fernando Alonso of Spain celebrates on the podium after finishing second in the Indian Formula One Grand Prix