Five days before the four Nirbhaya case convicts are to be hanged, Delhi's Tihar Jail today asked for a new date, saying the execution cannot take place until mercy petitions filed by the convicts are settled. The convicts, Mukesh Singh, Vinay Sharma, Akshay Singh and Pawan Gupta, are to be hanged at 7 am on January 22, a Delhi court declared last week, putting out a death warrant in the seven-year-old case.