For understanding why only Kashmiri pandits observe fast on the shuklpaksh ashtami of every month, it is very essential to know about the historical significance of Mata Kheer Bhawani and the relevance of ashtami in light of that.
Kheer Bhawani temple is dedicated to the goddess Mata Maharagina Bhagwati. Legend is that Mata Maharagina was pleased with the devotion of Ravna who appeared before him and he got the image of the Goddess installed in Sri Lanka. However, the Goddess became displeased with the vicious life of Ravna and did not want to stay in Sri Lanka. Therefore, she is believed to have instructed Lord Hanuman to get the image from Sri Lanka and install it at the holy spot of Tul Mulla. In Kashmir Ragniya is also known as Tripura, while in (Sri) Lanka, the Mother Goddess was called Shayama.
It is said that the night during which Mother Goddess came from (Sri) Lanka to Kashmir was named Ragniya Ratri. In Kashmir a number of shrines are named after Mother Goddess like Tiker, Bhuvaneshvar, Manzgam (Noor-abad) Bheda, Loqraerpur, Manigam, Raithan and Baedpur which have equal divine and spiritual significance, but the shrine at Tul-Mul is the most famous one and hence the focus of yatris. 360 springs (nagas) are said to have gathered there. Ragniya is a Sattavie form of Mother Goddess, i.e. the form of tranquility and bliss. TULMULA was then surrounded by four villages – Bhavneesh,Tungeesh, Labdavan and Voker.
Bringesh Rishi has made a reference to it in Bringesh Sahitya. The reference of sacred spiring is quoted by Kalhan in Rajtarngni also. Thousands of years ago, many floods occurred in Kashmir and the sacred spring of Tula Mula was inundated under and the holy place could nowhere be traced. At last, Kashmir’s Yogi Krishna Pandit Taploo of Bohri Kadal, Srinagar had a dream in which the Goddess appeared to him and directed that she would swim in the form of a snake at the proper place and that he should stick large poles to demarcate the holy spot in the marshy land. Subsequently, when the water subsided a unique heptagonal spring was discovered which was seen flowing from west (sheer or head section) to the east (padh or feet). The holy spring was known to change its colour with various hues of red, pink, orange, green, blue, white and black.The spring has unique shape with seven corner points which symbolise the seven points of kundlani: Muladhara, Swadhisthans, Manipura, Anahata, Vishudda, Ajna, Sahasrara.
That is the reason for spiritual attainment great saints like Shankaracharya and Swami Vivekananda stayed here and meditated for spiritual elevations. Swami Vivekananda has mentioned that when he was in Tulmula he saw the water of the pond changing to different seven colours and had his spiritual attainments realised. This is the only holy place where great saints sit in smadhis for their kundlani awakening. The myth also goes that Ragyina Bhagwati only fulfils the spiritual aspirations of the devotees unlike Hari parbhat, Zeyshta devi, Zala devi and other Devi’s where the devotees apart from spiritual other wishes also get fulfilled who with clean heart offer the worships. Tulmula is the only shrine where one cannot offer any tamsik, non veg. sacrifices to the mata because of her being the only satvik goddess. That is why no one enters the premises if he has taken non.veg. This is not in the case of other shrines, temples which are the abode of zala, parbhat, Zeyshta devi where non veg. is offered to goddess to please her.
When the spring was discovered before reaching the holy place of Tulmula the hawan at seven villages was first to be performed which started from Vichar nag, Nagbal, Dudrhoam, Boas, Lodvan, Wokur and the last one Tulmula.
It is said that people on hearing about the formation of holy spring used to cross the marshes by walking over tough roads growing in the sumps to reach the holy spiring. The curiosity of the spiring spread further when the learned Brahman Sh. Govind joo had a vision of the Goddess who manifested herself as a serpent. The devout brahman carried a vessel of milk arranged a boat and rode through the meshes of Tulmula and upon reaching the sacred spot slowly poured out the milk and offered that to Mata. Soon the devotees hearing about the sacred place started reaching there from Dugd ashram now known as Dudrhama to offer the prayers at the mystic spiring which is only and one in the whole of world where Nagraj and the Ashtnagraj reside.
In 1867 Devaan Narsingh Dayal initiated to clean the spiring, and innumerable devotees participated in that. But some of the devotees did not perform the cleansing of the spiring with true bhakti nd rather some of the devotees entered the sacred place after having had tamsik meals with which the sanctity nd piousness of the spiring seems to have been disturbed as a result of which the wrath of Goddess resulted in biggest epidemic in the area. The people then realised that some wrong souls might have done some sinful activities at the sacred place and it is said that people in large numbers offered prayers with broken hearts for forgiveness. Milk and kheer was offered to mata to save them from her wrath. That is why we also call the matas abode as ksheer Bhawani. The epidemic was spreading and seemed to have no full stop. The legend is that then a grand Hawan was performed on the day of shukulpaksh zeyshta ashtami to please mata and after purn ahoti it was decided that every year the hawan shall be performed and fast on every Ashtami of shuklpaksh shall be observed and it is from that time all the Kashmiri pandits started keeping fast which still continues. Also it was decided that no body would be allowed to enter the parisar who take tamsik meals and from that period no Kashmiri pandit family eats tamsik meals on this day of ashtami which still continues.