Environmental Engineering

Candidates with Masters degree in Civil / Environmental / Mechanical / Chemical / Agricultural Engineering or in a related engineering branch are eligible for PhD in Environmental Engineering in majority of Indian Universities. Few Universities allows exceptional graduate students of above mentioned branches direct admission in PhD. You may refer to target university websites for minimum cut off marks for admission in PhD.

Yes, energy engineering is a growing sector in India. Hydro, Solar, Nuclear, Tidal are some of the energy sources which are preferred as energy sources in various parts of India. Yes, it's a good specialization to pursue in engineering.
However, when we speak of the placements through TNAU, they differ. The actual campus placements are not very impressive and hence the course is not very popular through TNAU.
In case the students do pursue this field then it would be self placements through which they can build established careers.

Hi Rishabh,
You must take the GRE and have a good GRE score. Top universities are highly selective and therefore the top ones. 64% is not enough so you must bank on your GRE score, work experience, SOP, LOR, TOEFL score and overall profile.