Infrastructure investments, by their very nature, can have significant impacts on people and the environment, both beneficial and harmful. The Asian Infrastructure Investment Bank (AIIB), alone among the multilateral development banks (MDBs), has a specific mandate to focus on infrastructure. Four years after it went into operation, the bank is undertaking a review of its environmental and social standards. This review can help shareholders and the bank decide which development path it wishes to follow. The time for business-as-usual, high carbon, extractive development is over. MDBs, funded by the public, including the AIIB, must play their part in changing the course of financial flows away from dirty, harmful investments towards more inclusive, innovative, people- and nature-centred development. A new report, based on evidence from the AIIB’s investments to date, recommends several urgent areas for improvement.