Congress President Sonia Gandhi is back in Delhi from her operation in the US. Sources say she flew in early this morning, and is now at her home at 10 Janpath. The UPA President has been in the US for an operation. The Congress said it would not confirm the nature of her medical problem. Different media reports said Mrs Gandhi was at the Sloane-Kettering Cancer Centre in New York, though this was not confirmed by Congress spokespersons.