Infrastructure investment company 3i Infrastructure saw income increase across its European portfolio in the first quarter.Portfolio income, which comprises dividends and interest receivable from portfolio assets, totalled £19.5m in the three months to June 30th, up from £17.9m the year before.This reflected "the steady underlying operational and financial performance of the investments", 3i said.During the period, the company committed to invest £4.6m in a primary public private partnership (PPP) project to build a new campus for Ayrshire College in Kilmarnock, Scotland."The European portfolio continued to perform well operationally and financially and to generate good levels of income, consistent with the company's objective of paying an annual dividend of 5.5% of its opening net asset value," said Chairman Peter Sedgwick.Meanwhile, the company said that the valuation of its holding in the 3i India Infrastructure Fund was helped by a 29% increase in the share price of listed firm Adani Power.Before the end of the quarter, 3i received £7.4m of proceeds from selling off a portion of its holding in Adani Power to "capitalise on the rally in the share price".As previously announced, 3i doesn't plan to make any further investments in India and expects to realise its current investments over the next few years.BC