"A very special grand prix. I don't know what it is about this circuit but I really like the flow of it," said Vettel, who has now led every single lap for three successive races - a feat last managed by the late triple champion Ayrton Senna in 1989.
"This was another good step for us but there's still a long way to go."
Australian Mark Webber finished third for Red Bull, complaining of a loss of KERS boost after 45 of the 60 laps and being passed by Alonso three laps later.
"It is not easy at the moment to fight the Red Bull but we will never give up," said the Spaniard in a podium interview in front of the cheering crowd.
"Well done to Red Bull and Sebastian but we want to be happy and enjoy it in Brazil (the last race). It is not only here. I am sure we will do it."
In Image: Third placed Red Bull driver Mark Webber, right, of Australia sprays champagne onto teammate and race winner Sebastian Vettel of Germany as they celebrates on the podium after the Indian Formula One Grand Prix