Application of Act to establishments allows government or commissioner notification to extend statutory coverage by agreement or notice. The Act prescribes its application to specified factories and other establishments meeting the employment threshold, while granting the Central Government power by notification to specify additional classes of establishments or lower the threshold after notice. Independently, the Central Provident Fund Commissioner may, by notification, apply the Act to any establishment where the employer and a majority of employees have agreed, with effect from the date of agreement or a later date specified.