In a country torn along sectarian lines, arrival of Muharram is marked by security plans, blocked routes and safety alerts. Terror threats loom over the country as mourners remember the Battle of Karbala; a hand grenade lobbed at an imambargah, a religious leader shot dead or a clash between two groups during a procession have come to define the holy month in Pakistan. This year was no different; in a shocking targeted attack, four Hazara women were killed and another was injured when a gunman opened fire on a bus in Quetta.While the overall security may have improved slightly, incidents like these are reminders of the multifaceted security challenge Pakistan faces today.Below is a timeline of attacks on mourning processions and imambargahs across Pakistan during the month of Muharram in past few years.October 22 – Twelve killed, 21 injured in bomb attack on an imambargah in Bolan district of Balochistan.October 28 - A nine-month-old girl killed, eight injured in hand grenade attack on Islamic Research Centre at Ayesha Manzil, Karachi.October 30 – Two injured in attack on an imambargah in Gulistan-e-Jauhar, Karachi.November 5 - Three killed, 28 injured in IED explosion near a Muharram procession in Orakzai.November 10 - Two policemen killed, two injured in attack outside an imambargah in Rawalpindi.November 9 – Three killed in gun attack on two imambargahs in Gujranwala. 3November 13 – Twenty injured in three bomb and grenade attacks near imambargahs in North Nazimabad and North Karachi areas of Karachi.November 15 – Eight dead, more than 80 injured in sectarian clashes during Muharram 10 procession in Rawalpindi. In Karachi, three policemen injured in hand grenade attack near Zainul Abideen Imambargah.November 18 - Three killed in the clash near an imambargah in Kohat.November 23 – Seven killed, 28 injured in back to back bomb blasts on a busy street in Karachi’s Ancholi area.November 18 – Three killed, 12 injured in an explosion near Imambargah Mustafa in Abbas Town, Karachi.November 21 - Three killed, 11 injured in two bomb blasts near the Haider-e-Karrar Imambargah in Orangi Town, Karachi.November 21 – Twenty three killed, 62 injured in bomb attack on a procession in Rawalpindi.November 24 - Eight killed, 30 injured in explosion near a Muharram procession in DI Khan.November 25 – Five killed, 70 injured in bomb attack on a Muharram procession in DI Khan.Note: This is in no way a complete list and only mentions violence reported in news articles; the list also doesn’t include targeted attacks on individuals.