Leaders and workers of the Congress' Delhi unit staged a demonstration here on Thursday demanding SEBI chief Madhabi Buch's resignation from her post and the constitution of a joint parliamentary committee to probe the Adani issue. The protest at the Jantar Mantar was attended by Delhi Congress chief Devender Yadav, senior leader Sachin Pilot, Kanhaiya Kumar and Udit Raj, among others. The Congress wants an impartial investigation into the matter, Pilot said. The opposition party has stepped up its attack on the government after Hindenburg Research launched a fresh broadside against market regulator SEBI chairperson Madhabi Buch, claiming she and her husband had stakes in obscure offshore funds used in the alleged Adani money siphoning scandal. Buch and her husband have denied the allegations levelled against them as baseless and asserted that their finances are an open book. The Adani Group has also termed Hindenburg Research's latest allegations as malicious and manipulative of