On 24 July 2012, Mangala Gauri puja and vrat begins in Telugu, Kannada, Marathi and Gujarati calendars. Mangala Gauri Vrat (Shravan Mangalvar Puja) is the most auspicious vrat dedicated to Goddess Gauri (Goddess Parvati), observed on Tuesdays in Shravan month. 24 July is the first Tuesday in Shravan month 2012 in the above calendars followed in Andhra Pradesh, Karnataka, Maharashtra and Gujarat respectively.
The other three Mangala Gauri Pujan dates in 2012 are: July 31, August 7 & August 14. Know about Mangala Gauri Vrat Puja procedure here.