Aditya Birla Group has invested about USD 20 billion, mainly in manufacturing space, as it looks to be among the top two players across the segments it operates in, a top company official said on Saturday. Speaking at the Hindustan Times Leadership Summit, Aditya Birla Group Chairman KM Birla said the group firm has taken tough decisions, including the acquisition of Novelis by Hindalco, to build scale and aims to expand cement business from 100 million tonnes to 200 million tonnes over the next 10 years. He said most of the group's investments are long-term, with a business outlook over the next 15-20 years, while consumer businesses have a shorter span. "We have USD 20 billion of announced investments that are on the ground. Obviously, you look at it because a lot of them are in the manufacturing space. You would look at the next 15-20 years. Shorter than that doesn't make sense in that kind of business... If, on the other hand, you're looking at fashion retail or jewellery retail