The Congress has closed the doors on an alliance in Delhi, Arvind Kejriwal stressed today in an interview to NDTV, stating that his Aam Aadmi Party (AAP) was preparing to contest alone in the capital in the national election just weeks away. "They (Congress) have refused to go for a gatbandhan (alliance). It appears they are firm," Arvind Kejriwal said. He explained that despite their bitter rivalry, he was in favour of a tie-up with the Congress to tackle what he felt was the "biggest challenge" to the country, "To remove the Narendra Modi-Amit Shah duo from power." But the Congress had refused, he repeatedly said. "All doors are closed and we are preparing to contest alone," the Delhi Chief Minister said.