when a Tsaddik passed away in the middle of nowhere in Russia, Siberia or Ukraine, and in the course of time the Jewish community migrated to other countries and no jews are left in that location.... is it allowed to take the Tsaddik. I mean if he was buried like 100 years ago or so. Is it allowed to take him to Israel or is it better not to touch the cemetery?

ב"ה Shalom In principle, it is a most severe thing to remove a deceased person from their grave. The exception is bringing a deceased person to Eretz Yisrael, which is permitted and this is written in the Shulchan Aruch Yoreh De'ah 363:1 and it is the ruling of other great contemporary Rabbis. In each individual case there may be circumstances which may involve other considerations before a final ruling. הר-צבי (יו"ד רעד), אגרות-משה (יו"ד ח"ב קנד), ציץ-אליעזר (חי"א סי' עה), שבט-הלוי (ח"ב רז ) ויחוה-דעת (ח"ד נז) All the best