Why doesn't Mumbai reclaim more land?

Was watching some history videos this weekend and got reminded that Mumbai was formed out of 7 small islands. If the British could build and reclaim land back then in such adversities, and we’ve grown leaps in engineering and development since, why aren’t we claiming some more land to the west? I get that it could impact aquatic life, but wouldn’t it also partially help address the population crisis? Would love to hear your thoughts !