Hi 

This is Ritika

According to me in my point of view and my experience (as because I am doing b.tech in West Bengal ).

Top ten college in Kolkata is 

1.Heritage institute of Kolkata

2.Institute of Engineering and Management, Kolkata

3.Techno India University, Kolkata

4.Techno India, Salt Lake

5.RCC Institute of Information Technology

6.Future Institute of Engineering and Management, Kolkata

7.Bengal Institute of Technology, Kolkata

8.Calcutta Institute of Engineering and Management, Kolkata

9.BP Poddar Institute of Management and Technology, Kolkata

10.Meghnad Saha Institute of Technology,

Hope My answer helped you

Thank you

Top private  engineering colleges in kolkata are-

1. Heritage institute of technology 

2. Institute of engineering and management 

3. Techno India university 

4. narula institute of technology 

5. RCC institute of information technology 

6. Future institute of engineering and management 

7. Bengal institute of technology 

8. Calcutta institute of engineering and management 

9. BP podar institute of management and technology 

10. Guru nanak institute of technology