As Japan commemorates the 10th anniversary of the tsunami, Mark Willacy travels along the north-eastern coast to meet the fishermen and communities affected by a $17 billion project to build a new seawall running 400km.

New Zealand's clean, green image hides a dirty truth. Polluted by intensive dairy farming, its waterways are some of the most degraded in the world. Will the Ardern government clean it up or will the Maori take control?