Explanation

The 1962 constitution was remained active for 7 years (1962-1969)

President Ayub Khan promulgated the Constitution of 1962 on 1 March 1962

It finally came into effect on 8 June 1962

In 1962 constitution:

• The presidential government system was introduced 
• Urdu and Bengali was Declared as the Official Language 

Iskandar Ali Mirza, the first president of Pakistan abrogated the constitution of 1956 

Ayoub Khan was made chief of martial law after this abrogation

Ayoub Khan enforced the new constitution on 8th June 1962

Yahiya Khan abrogated the 1962 constitution and became CMLA