Unfortunately from April 1, 2019, no. :(
If you have enrolled for Aadhaar, you are bound by law (Section 139AA of the Income Tax Act 1961) to quote it, irrespective of whether or not it has been linked with PAN.
From the latest (2019) Central Board of Direct Taxes rules published <strong>here</strong>:
>...139AA. (1) Every person who is eligible to obtain Aadhaar number shall, on or after the 1st day of July, 2017, quote Aadhaar number—
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> (i) in the application form for allotment of permanent account number;
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>(ii) in the return of income:...
More info <strong>here</strong>.