What is difference between iit collage and nit and Private collages example sastra university

Hi Aspirant,
IIT's are the premier engineering colleges of the country.They are government colleges and are centrally funded.Also,they take admissions through JEE ADVANCED.They are probably the set of best engineering colleges of the country and provide world class facilities.
NIT's come next in the ladder after IIT's.They are also centrally funded and provide facilities to the students almost same or below the levels of IIT. (Some old NIT's provide almost the same levels of everything).
Private engineering colleges are the colleges which do not the central funding.So,the student himself has to bear all the charges of his education. (In IITs and NIT's also the student has to pay but the central government also bears some part of the expenses).
There are some private colleges which provide education and placement facilities which are at par with the IITs(example BITS,Pilani).
Hope this helps.