Our Tzibur in the chassidishe Shul in Zürich which is a main point and a minjan factory never ever davens Tachanun in Mincha. I asked a couple of times what the reason was but nobody was accountable for this and nobody could explain me why. I couldn’t find any valid reason in MB or SHO. Can you please advise me if there is an explanation for this?
The minhag of many Chassidish kehilos is not to say tachanun at mincha. This minhag is recorded in many Chassidic and Sefardic sources. A number of explanations are offered:
1 they often daven until after shkiya, and according to many opinions tachanun may not be said after shkiya, so a blanket rule was instituted so as never to come to saying after shkiya, which in some kabbalistic sources danger is associated with this practice.
2 tachanun by mincha requires intense concentration, which most people don’t have in the middle of their day
3 after it is night in Israel tachanun should not be said even in other parts of the world
Sefer Nimukei Orach Chaim, Shu”T Dvar Yehoshua Y:D 3:74, Zivchei Zedek siman 9 [minhag bahdad], Sefer Shulchan Hatohar Siman 22.