What exactly are you trying to exempt from US income tax?

Item L (which flows to Line 22) is not usually applicable to Article 21(2), which provides to Indian students and trainees "the same exemptions, reliefs or reductions in respect of taxes available to residents of the [US]".  This refers generally to standard deductions, personal and dependent exemptions (which are for $0 under TCJA), and various other credits that are not otherwise availed to other NRAs and even Indian tax residents who are not students and trainees.

What you should do is to go to the Nonresident Alien Information Worksheet, check the box for Check this box if client is eligible for benefits of Article 21(2) of U.S. - India Income Tax Treaty.  If your client has dependents that may qualify for ODC, you will make the input in Part III on the same input screen.