Under what circumstances can the 'National Emergency' be proclaimed by the President of India? What are the consequences when such a proclamation remains in force? When was it last imposed in the country?

Article 352 of the constitution gives about proclamation of National emergency. Constitutions 'National emergency' can be proclaimed: (1) Armed secession (Lt & On CAA) as earlier internal insurgency, wars etc (2) External aggression: when war or external threat to nation (3) On written recommendation of the Cabinet (50/PCA) (4) On resolution passed by both Lok Sabha and Rajya Sabha by special majority Consequences of proclamation: (1) On Fundamental rights: i Article 19 has been annulled in case of external aggression only (44th CA) ii Articles 20 & 21 cannot be suspended or President (2) On legislation: i Parliament has control over state list subjects & make law be state also has concurrent power ii On Executive: Executive power of states is taken over by Centre iii Financial: President can reserve money bills and ask for financial prudence by states iv Restore: President can unmake the state legislative assembly & parliament by one year Imposition -3 times imposed => 1962, 1972, 1975 last imposed in 1975 due to internal aggression by Indira Gandhi