You'l find a lot of description and significance of Uttrayan once you google about it. Hence I wouldn't go into the formal details but make a brief mention of what it is like in my own words.
In India, especially in the Western region, most houses have their private flat terraces where every year on January 14th, entire towns of family, friends, strangers, everybody crowds upon to have fun, eat, make merry and celebrate a holiday filled with friendly kite fights. There's music, there's hooting, there's good food and with all this in the background one can watch the sky change color 'like a rainbow in the glittering sun'. It's probably one of the most colorful and lively festivals of India. At night, after the sun sets, the party is still not over. People fly special kites that have small lamps lit inside, the energy and the fun flows into the night with some more music, dance, food and good times. The following one image is outside Meena's work, but i decided to include it anyway for you to be able to easily comprehend what i was talking about.
'Manja' is the string attached to the kite, that soars the skies, and engages in the friendly kite fights. For the pros, who cuts how many kites is a big deal about Uttrayan. For this purpose the 'Manja' is processed through rice and ground glass - literally, to make it strong. Different colored dyes are added simply to make it more colorful. At the end of the day, the more kites you might have cut the more wounded your hands would be owing to the glass coated strings. But the fun loving people don't mind this, greater the wounds, higher the score! It's more symbolic of the victories of the day.
Coming back to Meena Kadri. She is a practicing graphic designer/creative director and an academic in design. To me, also a very promising photographer, she has done her undergrad in Anthropology and a Masters in Design. Currently based out of New Zealand, professional pursuits have taken her travelling the globe to places like India, China, Berlin and other places in Europe. She interestingly reflects these excursions on her blog with some even more interesting reads related to social landscapes surrounding specific cultures and their connection with specific art forms and graphics. Check out more of her photographs here. Meena calls herself the 'Meanest Indian' - the witty pun just makes me smile. It's been nice to have come across your work Meena and thank you for the lovely pictures :)