Why are tubeless tyres not popular among indian cars?

Tubeless tyres have lower maintenance than tube tyres, for apparent reasons.  It’s altogether a different issue, though it cannot be discounted, that the required infrastructure is not available in smaller cities, as pointed out by you.  Regardless of that, it’s recommend that we should prefer tubeless tyres to tubed tyres for the following considerations…

Penetrations into the tubeless tyre are sealed off by the rubber itself, resultantly leakage of air does not take place and if it does, it is minimal – greatly reducing the hazards from punctures.

In case of a total loss of air inside the tubeless tyre, it is likely that the bead will collapse inside the rim-well rather than come-off it. It is free from other tube troubles like ballooning, open splice, spurious tubes, pinholes, tube mounting damage etc. The cost of a tube and its maintenance are avoided.

The biggest advantage is, however, the puncture problem that none of us have control over. There have been a number of gruesome high-speed fatalities on the Mumbai-Pune expressway caused by tyre blowouts.  At speeds in excess of 100kmph high temperatures are generated. These high temperatures expand (in some cases this tube is over-inflated too, which only aggravates the situation) the tube and a sudden sharp penetration at high speed causes the tube to burst very easily. The air expelled at high pressure forces its way out of the tyre from around the rim and the tube valve hole. In some cases the pressure exerted by this escaping air is strong enough to rip open the tyre. A burst tyre causes a sudden loss in traction which is sufficient to throw the vehicle off course violently.

The primary advantage of tubeless tyres is on account of its internal construction and materials used. A tubed tyre is vulnerable to friction and heat generated between the tube and the inner surface of the tube which reduces life of the tube. In a tubeless tyre the inner layer of the tyre is the tube itself. This layer is made of a material like halo-butyl/chlorobutyl which is basically resistant to heat and reduces permeation of air. The weight of the tube inside a tyre adds to the unsprung weight affecting handling characteristics and overall performance. The lack of a tube reduces unsprung weight and improves dynamic ability. It also reduces rolling resistance caused by friction between the tyre and tube. The lower rolling resistance, lesser weight and the tubeless tyre's capability to uniformly retain air, improve fuel efficiency (marginally).