A coalition government in a parliamentary system is a government in which multiple political parties cooperate, reducing the dominance of any one party within that "coalition". The usual reason for this arrangement is that no party on its own can achieve a majority in the parliament. A coalition government might also be created in a time of national difficulty or crisis (for example, during wartime or economic crisis) to give a government the high degree of perceived political legitimacy or collective identity it desires while also playing a role in diminishing internal political strife. In such times, parties have formed all-party coalitions (national unity governments, grand coalitions). If a coalition collapses, a confidence vote is held or a motion of no confidence is taken.

When no single party gets absolute win in lok sabha it joins other party to win the elections, and when the formed party gets elected and forms the government that government is known as coalition government