The 2009 model Maruti Alto has 12-inch rims with 4 holes and 100 PCD (the distance between the holes on the rim). The Maruti Swift uses 14-inch rims with 4 holes and 100 PCD and 15-inch rims in the ZXi / ZDi variant. If you put 14-inch Swift rims, you will have to put very low profile tyres, otherwise it will hit the fenders. I would suggest upgrading to 13-inch rims instead and upsizing the tyres slightly. I don't think you can put 14 or 15 inches on the Alto without doing any suspension modifications. It's not advisable.
Roshun, I once saw this Alto running on 14-inch wheels. He used low-profile tyres. The car looked like a hatchback on stilts by which I mean it looked plain ugly. This guy had gone for wider tyres as well which were sticking out of the wheel arches. Isn't that dangerous?
NikilSJ Dangerous - yes. The car's handling would be completely ruined with low profile tyres that are too wide for the car, and will make the ride quality very stiff. And with tyre sticking way out of the body line, it would be a pain in traffic as well. If he's carrying a car full of people, I'm sure he would have issues with the tyres rubbing the fenders as well. When upsizing the rule is to stick to within 2% plus or minus stock size for outer diameter and about 10% plus for width.