Navratri is a nine day eloquent celebration for Maa Durga. There are nine colours acquainted with the nine days. Here are details about the colours and its significance.

Day 1- Royal Blue.
It is a day for Brahmacharini, who stands for calm with grace and thus royal blue signifies wisdom, strength and intelligence.
Day 2- Yellow
Yellow stands for happiness, cheer and brightness which gives a sense of positivity
Day 3- green
Green signifies growth and prosperity
Day 4- Grey
Skandamata, The War God is worshiped on this day, Grey represents the strength of a mother while protecting her child.
Day 5- Orange
It is the day of Saraswati Puja and the colour represents knowledge and energy
Day 6- White
This day is dedicated to Goddess Katyayani who stands for peace, purity and coolness.
Day 7- Red
A day dedicated to Goddess Kalaratri known for her fierce avatar. Colour stands for anger, energy and radiance
Day 8- Sky Blue
The colour is associated with wisdom and loyalty
Day 9- Pink
Maha Navmi is the last day of Navratri and it signifies optimism