Engineering Admission Process

Yes, you are eligible as you have completed 3 years engineering Diploma after 10th.

NIT considers the category rank for admission.

Lateral entry admissions depend on the number of seats vacant in 2nd year, but still some of the best colleges are Heritage, IEM, Haldia, etc.

Merit and management quota basis.

You have to qualify the LEET entrance exam.

Dear Papiya,
There are many good colleges providing lateral entry in civil engineering. Some colleges are mentioned below:
Delhi College of Engineering, PEC Punjab, LPU Punjab, Dehradun Institute of Technology, Graphic Era University, College of Technology Pantnagar, etc.

Hello Akash,
A Diploma is a Diploma and a degree is a degree. You can call by any name. Three years course after 10th. Lateral admissions to 2nd-year of engineering are allowed in a majority of colleges. Rules for this are state specific.
You can raise a further query to clarify.

B.Tech through lateral entry admission process varies in different engineering colleges. Admission in DTU is based on marks scored in Diploma in engineering. The admission in Manipal University is based on its B.Tech entrance examination. Some states conduct LEET exam for lateral entry admission in the state engineering colleges. You are advised to make target universities list and then look at their website for lateral entry admission process.