According to Official Guinness Records,
The most questions asked by a TV talk show host in 6 hours is 670, achieved by R. Sreekandan Nair, Flowers TV and Swayamvara Silks (all India) at MGM School in Kottarakkara, Kerala, India, on 18 March 2018.The attempt was organised to celebrate 1,000 episodes of the Sreekandan Nair talk aired on Flowers TV.
For a complete list of 2018 records, please visit 2018 Guinness Records in India.