Udaan, the fastest Indian startup to achieve unicorn status, has raised $585 million in its latest round of funding, valuing the online business-to-business marketplace at $2.5-3 billion. The Series D round saw investments from Tencent, Altimeter Capital, Footpath Ventures, Hillhouse, GGV Capital and Citi Ventures. Existing investors Lightspeed Venture Partners and DST Global also invested in the round. The B2B marketplace plans to use the newly raised funds to deepen its presence across India and add new product categories.