What happened to Airtel’s ₹499 Wi-Fi plan in Tamil Nadu? Why are some customers unable to get it despite Airtel still listing the plan?

Airtel’s ₹499 Wi-Fi plan still exists, but it’s mainly available where Xstream Fiber is installed.
If your area only supports AirFiber, Airtel may offer higher-priced plans instead. So the issue is local availability, not necessarily cancellation of the ₹499 plan.