of its unobligated balances authorized under sections 5305, 5307, 5310, 5311, 5329(e)(6), 5335, 5337, 5339, and 5340 of title 49, United States Code, as of September 30, 2020, under this proviso. Transit infrastructure grants For an additional amount for buses and bus facilities grants under section 5339 of title 49, United States Code, low or no emission grants under section 5339(c) of such title, the passenger ferry grant program as authorized under section 5307(h) of such title, and the demonstration and deployment of innovative mobility solutions as authorized under section 5312 of such title, $510,000,000, to remain available until expended: Provided , That of the amounts made available under this heading— (1) $374,000,000 shall be available for the buses and bus facilities competitive grants as authorized under section 5339(b) of title 49, United States Code: Provided , That activities that increase green space surrounding a bus transportation hub structure are eligible for a grant under this paragraph: Provided further , That the minimum grant award shall be not less than $1,000,000