Thanks to @survivablyso for info about the pink on the palms!

Alta is a bright red dye or liquid color used to adorn palms and feet in simple patterns. Painting the soles with this red liquid dye and adorning the upper foot with elaborate designs to bring out the beauty of the feet, Alta is a common Indian tradition, particularly during religious festivals and weddings. A common ritual followed by the womenfolk in West Bengal, Alta is also known as Mahavar, which is dark pink in color. In fact, a Bengali bride is incomplete if her hands and feet are not adorned with Alta. In other words, Alta is another form of putting Mehendi or Heena. The Islamic invasion of India brought along with its new customs and traditions – henna or mehendi, being one of them.  Due to the increasing influence of Muslim culture, the usage of Alta was slowly replaced by Henna in other parts of India.

Alta is more prevalent in West Bengal, where a woman devotes as much attention to adorning her feet with Alta as much as she does to her hair and face.  Wearing Alta on Durga Puja is a common ritual for Bengali womenfolk.

In few parts of India, Alta is not only used as an adornment for the feet, but also used to perform an important post-wedding ceremony in which, the bride enters her in-laws home for the first time. Before entering the new house or house of the in-laws, the newly-wedded bride steps into Alta and then walks inside the home, leaving a trail of her footsteps. This trail indicates that Goddess Lakshmi in the form of the bride has now entered the home.

Alta is a very important part of Oriya wedding ceremonies as the color red stands for purity and prosperity.

According to Hindu Mythology, the images and sculptures of the Goddesses, particularly that of Durga and Lakshmi is painted with Alta.  The same is for depictions of Krishna and Radha.

Alta is an inherent adornment for mostly all the Indian classical dance forms such as Bharatnatyam, Kuchipudi, Odissi, Kathak, Mohiniyattam and Manipuri. It has been retained as a necessary part of the dancer’s make-up routine.   Alta is the most striking part of an Odissi dancer’s overall look as her hands and feet are intricately adorned with bright red Alta.  The red hands made the mudras (gestures) look splendid and dramatic.