When writ to be issued in spite of availability of alternative remedy

In Harbanslal Sahnia (supra), Lahoti, J, (as His Lordship then was),
relied upon Whirpool Corporation vs. Registrar of Trade Marks [(1998) 8
SCC 1] observing that in an appropriate case, in spite of availability of the
alternative remedy, the High Court may still exercise its writ jurisdiction in
at least three contingencies : (i) where the writ petition seeks enforcement of
any of the fundamental rights; (ii) where there is failure of principles of
natural justice; or (iii) where the orders or proceedings are wholly without
jurisdiction or the vires of an Act is challenged.