It is the beginning of a new month according to Sikh calendar. The beginning of the new month is announced in the gurdwaras and the relevant portion from the Bara Maha, Song of the 12 Months  by Guru Arjan Dev or sometimes Bara Maha by Guru Nanak Dev is read, which gives the Vak of the month. This day just marks the beginning of the new month and is not treated as being greater or better than any other day. It is to be kept in mind that Sikhs don-t treat this day as an auspicious day because according to Sikhs all days are same.