Mention any one important occasion when the President addresses a Joint Session of Parliament.

At the FIRST SESSION AFTER EACH GENERAL ELECTION to the Lok Sabha, the President addresses both Houses assembled together, outlining the policies and programmes of the government. (He also addresses the first session of Parliament each year, and may address a joint sitting summoned to resolve a deadlock over an ordinary Bill.)

One occasion only, so give one clearly. The two regular occasions are the first session after a general election and the first session of every year. Note that this address is written by the GOVERNMENT, not by the President himself — another illustration of his nominal role. Distinguish this from a JOINT SITTING called to break a deadlock over a Bill, where the SPEAKER presides.