To become a lecturer in India you have to clear CSIR-NET/UGC-NET/SLET/RET.

NTA conducts the UGC NET for the research work and lectureship. From July 2018 NTA taken over the charge of conducting UGC (University Grant Commision) NET (National Eligibiity Testing).
CSIR-NEt is conducted for science stream students.
Motto of both CSIR NET and UGC NET is same bt CSIR NET is conducted only for the science stream students.
SET is State Eligibility Test, conducted for different states. Every state conducts SET.
RET is Research Eligibility Test.

If you're Post Graduation is from Science stream, then you can appear in CSIR NET and if from other you can appear in UGC NET.
CSIR NET is conducted in 5 subjects whereas UGC NET is conducted in approx 85 subjects.