Elections
Subject to the Constitution, Parliament may by law make provision on all matters relating to elections to Parliament or State Legislatures, including electoral rolls, constituency delimitation, and all else necessary to properly constitute those Houses.
This gives Parliament the primary law-making power over the detailed rules of India's electoral system - how elections are actually conducted, constituencies drawn, and rolls prepared - through ordinary legislation like the Representation of the People Act, rather than these details being fixed permanently in the Constitution's text.
This is the constitutional basis for the Representation of the People Act, 1950 and 1951, which contain the detailed operational rules governing how Indian elections are actually conducted, separate from the Constitution's own broader framework.