Hello calvin as you are looking for phd in tamil nadu so by appreciating your decision here’s a list of top PhD colleges/universities in Tamil Nadu:

1. Anna University, Chennai

2.university of Madras, Chennai

3. Central University of Tamil Nadu (CUTN), Thiruvarur

4. Bharathiar University, Coimbatore

5. Bharathidasan University, Tiruchirappalli

6. Alagappa University, Karaikudi

7. Tamil Nadu Agricultural University (TNAU), Coimbatore

8. SASTRA Deemed University, Thanjavur

9. SRM Institute of Science and Technology, Chennai

10. Vellore Institute of Technology (VIT), Vellore

There are many more please choose according to your preference interest after exploring.