HYDERABAD: BJP State president K Laxman ridiculed Congress for planning to stage a dharna on the issue of reservation for SCs, STs, BCs and minorities. He said the Congress suppressed these communities for decades and betrayed them on various counts. “The then Prime Minister Jawaharlal Nehru had undermined the work of Dr BR Ambedkar,” Laxman said and alleged that the SCs have been treated as vote bank by the Congress for many years.