With a JEE Mains CRL of 4 lakh and an OBC rank of 1.5 lakh, and being a female candidate from Delhi, your chances of getting into IPU (Guru Gobind Singh Indraprastha University), IGDTUW (Indira Gandhi Delhi Technical University for Women), and NSUT (Netaji Subhas University of Technology) will vary depending on the specific program and the cutoff ranks for the OBC-NCL (Non-Creamy Layer) female category under the Delhi quota.

For IPU, the cutoffs for various B.Tech programs can differ significantly. With your rank, securing a seat in the top CSE programs might be challenging, as they usually have much lower closing ranks. However, you might have possibilities in some other engineering branches or at some of the affiliated colleges of IPU. It's crucial to check the previous year's cutoff lists for the OBC Delhi female category for all the B.Tech specializations offered by IPU and its colleges to get a clearer picture.

IGDTUW is exclusively for women, which can improve your chances due to gender reservation. However, with an OBC rank of 1.5 lakh, admission to the highly sought-after CSE and IT programs might still be competitive. Looking at the historical cutoff data specifically for OBC female candidates from Delhi for IGDTUW's B.Tech programs will be essential. There might be better opportunities in some of the other engineering branches offered at IGDTUW.

NSUT, being one of the premier engineering institutions in Delhi, generally has high cutoff ranks. While you have the advantage of the home state and female quotas, your OBC rank of 1.5 lakh might make it difficult to secure a seat in the core branches like CSE. However, similar to IPU and IGDTUW, it's advisable to check the previous year's OBC Delhi female cutoff ranks for all the B.Tech programs offered at NSUT. There could be possibilities in some of the other engineering disciplines.

In conclusion, while your percentile might not be very high, the Delhi home state quota and the OBC and female reservations can play a significant role. To understand your admission prospects accurately, you should thoroughly refer to the previous year's official cutoff ranks for each of these institutions, specifically for the OBC-NCL female category under the Delhi quota, for all the B.Tech programs you are interested in. Keep an eye on the JAC Delhi counselling process, as that is the common platform for admissions to these colleges based on JEE Mains ranks.