Since you are able to purchase a new Kia Seltos or Carens Clavis EV, we would suggest you not look at a used Tata Harrier or XUV700, as these are quite close in size, performance and features. If you are buying used, it makes sense to get something from two segments above. 

As to your query about a diesel or electric, yes, both are not likely to have a high resale value. There's certainly a cloud over diesel's long term future, and the pre-owned EV market is too nascent to judge future potential. 

We would, however, recommend the EV as you will be keeping your car for about 10 years, and in that time with your running you would save on fuel bills. Between the Hyundai Creta electric and the Clavis EV, we would suggest the Kia as it's very similar mechanically. But also offers you the benefit of the third row of seats, which is quite spacious and usable. 

While there are a lot of SUV options that fall within your budget, we've listed the top models worth checking out. Among the monocoque-bodied SUV options, there's Tata's Harrier and Safari, and the Mahindra XUV 7XO. These SUVs are large and have great road presence. Also, being monocoque SUVs, they score well on comfort and refinement. 
 

If you are looking for something more hardcore, there's the option of Mahindra's ladder frame SUVs, namely the Scorpio N and Thar Roxx. These SUVs are big on image and have a toughness about them that's very appealing. 

However, they are not as comfortable as the models listed above. 

A very Happy New Year to you too! 

Both the Tata and Mahindra cars are excellent choices, but of the two, we'd recommend waiting for the Mahindra XUV 7XO, whose launch is right around the corner. It will have a more modern interior and likely more features too, and going by its predecessor, the XUV 700. 

It will also have the more refined diesel engine and slicker manual gearbox. We will say the Tata Safari has the edge on space, especially in the third row, and its ride quality is slightly more comfortable. Plus, there will likely be a long waiting period for the Mahindra XUV 7XO once it is launched. 

So, if you are in a hurry, the Tata might be easier to get sooner. But in most other areas, the Mahindra comes out on top. Another consideration, especially for your elderly family members, is that ingress and egress to the cabin are slightly easier in the Mahindra than the Tata. 

Given your requirements, you should check the Tata Harrier and the upcoming Mahindra XUV 7XO.

The Tata Harrier is large and spacious, with ample room for front and rear passengers as well as a sizeable boot. The Harrier also feels tough and delivers on ride comfort. Within the Harrier line-up, the new petrol versions (prices of which will be announced soon) are the ones we'd recommend for you. 

The 1.5-litre turbo-petrol engine is smooth and delivers ample performance. Gearshifts on the 6-speed automatic transmission are also very nice. The Harrier petrol, however, isn't as quiet as we'd hoped. You can hear the engine - it's not loud but remains audible. 

Mahindra's upcoming XUV 7XO is essentially an updated version of the current XUV 700. Space is aplenty in the first two rows, and folding down the third row also frees up lots of luggage room. The XUV 7XO will use the same engines as the XUV 700, which means your options include a 200hp, 2-litre turbo-petrol and a 185hp, 2.2-litre turbo-diesel. 

The petrol engine is particularly exciting, delivering brisk performance (though fuel economy is poor). On the other hand, the diesel engine feels strong and is also refined as diesel engines go. Opt for the automatic transmission versions for the best experience.