Shrawan is one of the holiest months in Hindu calendar. Devotees of Shiva perform religious rituals and take bratas (fasting). Each Monday of the following month, known as Shrawan Sombar, is a special day in Shiva temples. Hindu devotees walk bare foot and with holy water to offer to the Lord Shiva.
Every Monday, devotees clad themselves in vibrant red, green and yellow clothes and ornaments and worship Lord Shiva.
Source: My Republica