40 in service 83 on order follow on order is expected once all units get delivered , a new aircraft called Tejas MK2 or MWF under development IAF will buy 200+ units of that aircraft.
The reason why IAF cannot replace entire fleet with indigenously developed fighter jets is the engine , all Indian made jets have to use American engines and supply of engines would stop if USA sanctions India
Indian made Kaveri turbofan engine didn’t produce enough thrust to power Tejas but It was built from scratch now India is working on a new 130kn engine for AMCA and it has to be completed in next 8-10 years time maybe after 10 years Tejas will have Indian made engines just like the Indian made UTTAM AESA Radar
Engine failure and technical snags plagues JLT JF17