The Tata Sierra is clearly the larger of the two cars and will give you more space than the Maruti Fronx, as well as a better ride, too. However, the base version of the Sierra isn't as well-equipped as the Fronx. 

More importantly for you, the versions that fit your budget come with the 1.5-litre naturally aspirated engine, which is quite weak in its power delivery and not ideal for you, given that you are mostly driving on highways. Thus, a high variant of the Fronx would suit you better.    

The Maruti Suzuki XL6 would best suit your requirements of mileage and performance. Against the others in your shortlist, the 1.5 litre petrol engine in the XL6 offers decent performance and refinement, but a noticeably better fuel efficiency. The engine has a mild-hybrid setup and, in our standard test cycle, returned a figure of 9.2kpl in the city and 17.0kpl on the highway. 

We assume, of course, you are comparing petrol versions across the three MPVs in your shortlist, given that the XL6 comes with only a petrol engine. If not, the Kia Carens and Hyundai Alcazar also have diesel engines, and these versions would be more fuel efficient than the petrol XL6. 

Yes, if your driving is primarily in the city, the combination of naturally aspirated petrol and a smooth automatic is the best option for you. Advantages of the Maruti Victoris are a slightly lower price and official fuel economy rating. 

However, do note that the Victoris uses a 6-speed torque converter automatic, while the Hyundai Creta uses a CVT, and in real-world use, the CVT is likely to be more efficient. The Creta outscores the Victoris in most other areas, too, including your requirement of comfortable back seats, where the Victoris is lacking in space. 

You could also check out the new Kia Seltos, which offers the same 1.5 petrol CVT powertrain as the Creta, but even better rear seat space and comfort.

We would recommend you look at the Maruti Suzuki Celerio. The Celerio will deliver well on the mileage and maintenance front, and it is also very easy to drive with a compact footprint, light controls and a good view outside. The car also secured a 3-star rating in the GNCAP crash tests, which is just about ok. 

If you'd like something better on this front, consider the Tata Tiago, which fares better with a 4-star rating. It offers a slightly better ride quality and stability at speed, but bear in mind the mileage will not be as good as the Maruti Celerio. Also, Tata dealers are not known to be very good with service.           

The Maruti Suzuki Baleno or even its sister car, the Toyota Glanza, would be a good option to buy. The car is spacious with comfy seats, and it is fuel-efficient too, both the manual and the automatic version (AMT). 

In our standard test cycle, we got 13.80kpl and 17.50kpl in our city and highway cycles for the manual, whereas the automated manual transmission (AMT) achieved 11.86kpl and 17.21kpl.  

The Baleno sits below 4 meters in length and is compact enough for the city. However, if you would like something smaller, consider the Hyundai Exter. It won't be as efficient, in the manual we got 9kpl and 14kpl for city and highway runs, but this is still good. Also, you will also benefit from a slightly higher seating position and a lower price.    

The new Hyundai Venue is a good option to consider. It is an easy-to-drive SUV with good visibility, a light steering, and a buttery-smooth 5-speed manual gearbox and clutch. The 1.2-litre petrol engine is very refined and smooth, and has adequate performance for city use. 

You could also consider a Maruti Baleno or Toyota Glanza. These are very user-friendly hatchback options in that price range.

Almost all cars today are equipped with basic safety features like ESP, along with ABS with EBD. It helps prevent an accident in the first place, and these also have 6 airbags to protect the occupants in case of a collision. 

Hence, as far as safety features go, most cars have you covered. That said, if you're looking for an automatic vehicle with an excellent 5-star BNCAP crash test rating within your budget, the Maruti Dzire AMT is the one to go for. 

The engine is smooth and refined, and even the AMT (automatic) is relatively smoother than many other options at this price. The cabin is spacious and comfortable, and it drives well on the highway, too. 

Alternatively, you could consider the Maruti Baleno or Toyota Glanza, both of which are 4-star BNCAP-rated vehicles.