I am Shia. We have Alam in our mourning for Imam Hussein and our strong youths carry them. Wsing an Alam in the mourning ceremonies is come from old tradition in Iran, India, Indonesia, etc.
'Alam is also of spiritual significance for the Twelver Shia Muslims. Though all Shias including those of Iraq, Iran, Afghanistan, Lebanon, Azerbaijan, Turkey, Bahrain, Saudi Arabia, and Syria carry 'Alams in their processions in Ashura, the ones in India and Pakistan are specifically of a different kind and have more of a spiritual significance. An Alam with a "Panja" on top of it is considered to be a religious flag of Islam, and it is said to be carried by the Prophet Muhammed, Hazrat Ali and Hazrat Abbas ibn Ali during battles or expeditions. The battle of Karbala further glorifies its importance. An Alam is usually seen during Muharram processions and at designated sites in Shia Mosques (1)
This kind of mourning is originated from those countries culture. Nowadays, Maraje do not confirm the symbols like pigeon, urceolate etc., these kind of symbols had been used in European countries (Christians) and in Safavieh and Ghajarieh period, came to Iran. I should say that Bidah is not acceptable in Shia religion but if Alam is a Symbol of Abbas ibn Abitaleb's Alam in Ashoora day and it does not have any fake symbol, it can remind Muslims the day of Ashoora.
Moreover there is no Hadith about this kind of mourning. "Prophet (pbuh) cried for his uncle and some women of Bani Abd Alashal mourned for his uncle too(2)".
Our Imams always have mourning ceremonies for Imam Hussein too but they often cry with Noheh.
SOURCES:
- Wikipedia: "Alam", 2014
- Abdul-Malik Ibn Hisham Hmyry, Sire Alnbvyh, translator of Sayyid Hashim Rasouli, Eslamiyya, vol 4, p 122.