The Central BUreau of Investigation (CBI) on Saturday raided the houses and offices of Vijay Mallya and his now grounded Kingfisher Airlines in Delhi and Bengaluru in connection with alleged fraud in Rs 900 crore loan given to him by IDBI Bank, a loan that has been declared as non-performing asset.

The raids were conducted at five places, officials said.

IDBI Bank came under the scanner in 2014 for granting an alleged bad loan to Kingfisher Airlines despite knowing its precarious financial position and negative credit ratings.

Mallya's airline has been grounded since October 2012.

A string of Indian banks have an exposure of nearly Rs 7,000 crore in loans to the airline, with the State Bank of India (SBI) leading with Rs 1,600 crore.

The Punjab National Bank, Bank of India and the Bank of Baroda have loan exposure of Rs 800 crore, Rs 650 crore and Rs 550 crore respectively.