I own a Celerio ZXi O that I’ve used for six years and want to upgrade to an automatic petrol car. My maximum budget is ₹15 lakh and I prefer low service and maintenance costs. Please suggest options.

Since you prefer a low service cost and an easy-on-the-pocket car, it would be better to stick to Maruti Suzuki as a brand. 

Maruti is renowned for low service and running costs and will offer peace of mind, just like the Maruti Celerio has. If you want a bigger car in particular, the Maruti Suzuki Brezza is a good option to consider. It has a roomy cabin, a comfy ride, the automatic is convenient for the city, and the running costs are low, too. 

Also, it has a good boot space and holds its value well. The other, more compact option would be the Maruti Suzuki Fronx with a turbo-petrol engine and a 6-speed automatic gearbox. It isn't as big as the Brezza, but it is very nice to drive and quite practical too. Both cars in their top-spec variants will fit in your budget.