What is the maximum gap allowed between the two parliamentary sessions?

Hint : The house meets to conduct its business during a period that is called a session. The president has the power to summon each house at regular intervals. The parliament must meet at least twice a year.

Complete answer :
The maximum gap allowed between two sessions of the Parliament is 6 months. Hence the parliament must meet at least two times in a year. In India, the parliament conducts three types of sessions each year.
Budget session: January to may
Monsoon session: July to August or september
Winter session: November to December

Note :The president has the power to summon the sessions of the parliament.The constitution of India provides for a joint session in the case of deadlock between the Lok Sabha and the Rajya Sabha. The joint session of the parliament is called by the President according to the Article 108. The joint session is presided over by the speaker of the Lok Sabha.