Each region has its own set of rituals and practices associated with this festival. A compilation of some of them here specifically with respect to the attire here.
List of the nine colours of Navratri to be worn by Goddess Durga as well as Devotees, with their significance:
First Day – Paadyami
Shailaputri Maa is the first amongst Navadurgas worshipped during Navarathri. On the first day this Goddess is dressed in a ‘Grey‘ saree. The colour to wear on the first day for devotees is ‘White‘.
Second Day – Dwitiya
Bharmacharini is the second form of mother goddess which is worshipped on the second day. It is believed that this goddess enlightens elegant forms with great power, divine and spiritual grace. The goddess is dressed in ‘Orange’ attire. The colour for devotees on this auspicious day is ‘Red‘.
Third Day – Tritiya
Chandraghanta is the third appearance of the goddess who symbolises peace, serenity, beauty and bravery in one’s life. She is decorated with a ‘Green‘ saree and on this day Gauri Vrata is done. ‘Royal Blue‘ is the colour of the day for devotees.
Fourth Day – Chaturthi
Kushmanda is the fourth form of goddess that is worshipped on the fourth day of Navratri. She is mainly considered as the creator of the universe. Mother goddess is drape with ‘Red‘ coloured saree. The colour for the devotees is ‘Yellow‘.
Fifth Day – Panchami
Skandamata is a face of Maa Durga always known for demolishing the demons. She is dressed in a ‘Blue’ saree and on this day and the Upang Lalitha Gauri Vrata is observed. Devotees are supposed to wear ‘Green’.
Sixth Day – Shashti
Katyayani is worshipped on the sixth day of Navratri. She is dressed in ‘Yellow‘ attire & devotees are supposed to wear ‘Grey‘ on this day.
Seventh day – Sapthami
Kaalratri is the seventh figure of Goddess Durga.The goddess on this day is supposed to be adorned with a ‘White‘ coloured saree. Maha Saptami is the day when Maha Saraswathi Devi is wordhipped and the colour of the day must be ‘Orange’ for devotees.
Eighth day – Ashtami
Maha Durga is worshipped on the eighth day(Durgashtami).The goddess is dressed in ‘Peacock Green‘ . On this day, ‘Peacock Green‘ is regarded as the colour for all.
Ninth day – Maha Navami
Siddhidatri is the form of Maa Durga for the ninth day of Navratri and is known to have great supernatural powers. This miraculous goddess is dressed in ‘Purple‘ attire and Maha Navami puja is done. ‘Pink’ is the colour of the day for ardent devotees.
Tenth day – Vijaya Dashami
Vijayadashami is the day of Victory of Good over Evil. The Goddess is dressed in Glowing Gold & the color for devotees is also Gold!
To summarize: Colors of attire advised on 9 days of Navratri
Day 1: White
Day 2: Red
Day 3: Royal Blue
Day 4: Yellow
Day 5: Green
Day 6: Grey
Day 7: Orange
Day 8: Peacock Green
Day 9: Pink