What is Rule 12 of Transaction of Business Rules,1961?

Under clause (3) of Article 77 of the constitution of India, The President in the exercise of the powers framed the Government of India (Allocation of Business)(AoB) Rules 1961, and the Government of India(Transaction of Business)(ToB) Rules, 1961,
Under Rule 12 of Tob,1961, In case of extreme urgency or unforeseen contingency, it empowers the Prime Minister to permit or condone a departure from the business rules, also in such situations, the process of examination and inter-ministerial consultations would need to be followed.
The Cabinet Secretary is the administrative head of the Cabinet Secretariat, the Cabinet Secretariat is responsible for the administration of the Government of India (Transaction of Business) Rules, 1961 and Government of India (Allocation of Business) Rules, 1961 facilitating smooth transaction of business in Ministries/ Departments. The Cabinet Secretariat is under the direct charge of the Prime Minister.
Why in the news?
Prime Minister Narendra Modi on Saturday, 23rd November 2019, invoked Rule 12 of the ‘Government of India (Transaction of Business) Rules 1961’ empowering to cancel the proclamation of President Rule in Maharashtra without the approval of the Central Cabinet.