Yes, IIIT Delhi is very strict in the sense that it ensures every student gets to nurture their talents equally here and enter the competitive world. It does not shy away from making the students work hard to prepare them for a bigger purpose.
The subsequent semesters bring in more workload and the strictness also increases. Additionally, it follows the Plagiarism Policy forbidding students from copying any assignment or labs from their peers or from the internet. Students therefore have to be thorough with their concepts and cannot rely on others. After every small interval of time that may be weeks or days of getting deadlines.
So yes, IIIT Delhi is definitely very strict compared to many colleges.