Hello shubham

For doing PhD in environmental engineering the minimum eligibility criteria is:
Masters degree in the requisite stream of study from a recognized University. However some college require the candidate to qualify relevant exam.

Hence, you can go for PhD in environmental engineering as having a Master degree is important.
Here are list of college that provide PhD in environmental engineering :

1. Gauhati University, Guwahati
2.University of Delhi, DU, Delhi
3.National Institute of Technology, NIT- Hamirpur, Hamirpur
4.Indian Institute of Technology -IIT (ISM), Dhanbad
5.Pondicherry University, Pondicherry

hi shubham,

i think you can do ph.d in environmental engineering with m.tech in highway engineering.usually the candidates who all are want to do ph.d in environmental engineering will choose m.tech in civil engineering.but highway engineering also comes under civil discipline,so i think it is possible.

please contact the institution/university to get clear idea on it.

all the best!!

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)