Guide me on selecting motor & controller

First tell us what you need. I have three ebikes, with three very different motors and controllers. Each one is perfect for what I have it doing. So let us know what your basic needs are. Long distance normal speeds, Short distance insane speeds, Climb a steep hill pulling a trailre full of groceries, etc. Where you live enters into it too. If you live in the USA OR Canada you have acess to several good dealers without shipping across the world. Budget is another big issue. A lot of people don't realize that a big fast motor needs a big expensive battery unless the ride is short enough for sla's.

Are you wiling to import into India where you are ???

That's easy then, many brands can do that. Lifepo4 batteries are best for long range, and the speed you want will be pretty close at 36v, but 48 is nicer most report. Lots of them ship from china. pingbattery.com is the best vendor, but on ebay, cammycc is developing a good reputation. For long range, get the 20 ah size.

Brand choice on the motor is largely a personal preference in that power range, and choice is often made based on trusting the vendor. But all the vendors we really trust are in North American continent.

Lots of golden motor vendors on ebay ship from china, and while the golden motor battery has been a poor choice, the motors seem to work as well as any, and actually, they have a very nice looking new controller coming out. Aotema motor is the one I use and like, sold in the US as wilderness energy brand. I suspect that an ebay vendor shipping from china might be cheaper than a motor shipped to north america and then shipped back your way. Australian vendors on ebay might be a good option though.