Hetauda, April 19 Former prime minister and senior CPN-UML leader Madhav Kumar Nepal today said implementing the new constitution presented a great challenge due to lack of responsibility among political parties. Speaking at a party cadres’ meeting in Hetauda, Makawanpur, Nepal held the political parties were irresponsible with regard to implementation of the statute. “Some of the forces are protesting implementation of the constitution, while some political parties are trying to neutralise the problems,” he said. Nepal further added that some of the forces protesting against the constitution making process were pushing the country backwards. Nepal said the Constituent Assembly elections and the constitution making processes were challenging in themselves but more challenging was its implementation. “The Madhesi people were badly affected due to protests carried out by Madhes-based parties and the border blockade,” he said. Nepal further clarified that the seven provinces were carved by his party against ethnicity-based federalism. “The dispute on federalism was resolved due to the liberal stance adopted by the Unified CPN-Maoist,” he said.