Rabbi Schneerson instituted a system of "[[mitzvah]] campaigns" called ''mivtzoim''; these encouraged Jews to increase their level of Jewish religious practise. They commonly centred on issues such as keeping [[kosher]], lighting [[Shabbat]] candles, studying [[Torah]], the laying of [[tefillin]], helping write [[Sefer Torah|Torah scrolls]] and teaching women to observe the ''[[niddah]]'' laws of Jewish family purity (laws pertaining to [[menstruation]] and ritual immersion afterwards in a pool of water known as a ''[[mikveh]]''). Lubavitchers went to street-corners, and rode in "[[Mitzvah tank]]s", mobile outreach centers, encouraging Jews to increase their religious observance. He also launched a campaign to promote observance of the [[Noahide Laws]] among [[gentile]]s.