Q. For city running about 5 km a day, which car to buy from Maruti Alto 800 or K 10?

I would say buy either the new alto with the safety features, mileage is slightly less but your running of 5kms per day will not make a huge difference unless you count pennies. But my money is still on the K10 with slight more cost but better engine and slightly better build.

You Should buy Alto 800 for better mileage. however if you are willing for good AC i.e. better comfort in economical cost in such case you can buy Alto k10. 799 CC engine does not support AC as 999CC leading to such variance.

Both have same mileage. I prefer k10 than alto 800 because of its power and ac function.