The government didn't wake-up overnight to freeze NGO's assets. Many NGOs were NOT filing annual reports that they were supposed to be filing, and their compliance(even pre-2014 norms) were not ensured by the govt.

UPA have used these NGOs to instigate protests in various state governments as Congress lacked strong real regional political activities and lack grass-root touch with people.

It was visible with the strong presence of NGO activists in the unconstitutional body of National Advisory Council.

Even after modification of norms, these NGOs were given sufficient notice and warning to file their reports.

On failure, to which govt took drastic measure.