A national emergency ceases to exist within 30 days of declaration unless the parliament sanctions the emergency with a special majority from both houses.
A special majority implies that those in favour of the emergency motion must be two thirds of those present and voting, and amount to a majority of the entire membership of that house. A Parliamentary resolution extends the state of emergency for up to six months, and it can be extended indefinitely by further resolutions in six-monthly increments.
Source: https://en.wikipedia.org/wiki/State_of_Emergency_in_India
Source: https://en.wikipedia.org/wiki/State_of_Emergency_in_India