Diploma

Dear Jay,
As you have already done a diploma, you are eligible for seeking lateral entry in B.Tech. One requires to qualify LEET as conducted by the technical education board of the state. Lateral Entry Entrance Tests are conducted on state level. But some colleges and Univerities too conduct Lateral Entry Tests. You will get direct admission to 2nd year of B.Tech if you clear the exam.
Some colleges that you can consider are:
Punjab University,Chandigarh.
IP University,Delhi.
Punjabi University,Patiala.
Thapar Institute of Engineering and Technology,Patiala.
KIITS University,Orissa.
Government College of Engineering,Pune.
Punjab Technical University,Jalandhar.
Sant Longoval Institute of Engineering and Technology,Sangrur.
Guru Nanak Dev Engineering College,Ludhiana.
Guru Teg Bahadur Institute of Technology,Malout.
Amity School of Engineering and Technology,Delhi.
etc,
If you are interested in any particular college, you can visit its official website to figure the eligibility criteria for lateral admission to B.Tech courses.
For the list of institutes, refer to the below link
https://engineering.shiksha.com/distance-learning-civil-engineering-in-india-categorypage-2-58-631-0-0-1-1-2-0-none-1-0#cateSearchBlock
(In the above link, you can refine the search as per your city preference)
Hope this helps.
Thanks
All The Best!