ISLAMABAD: Mourners took out processions nationwide on Wednesday to observe Yaum-i-Ashura amid heightened security arrangements. Yaum-i-Ashura is observed every year on Muharram 10 with solemnity to pay homage to Imam Husain — the grandson of Holy Prophet Muhammad (PBUH) — and other martyrs of Karbala. President Asif Ali Zardari said that the martyrs of Karbala had given a lesson to …