OPEC chief fuels oil investment debate

<p>From the BBC World Service: In an exclusive interview, the Secretary General of the oil producers cartel OPEC warns of &#8220;dire consequences&#8221; for the global economy if investment in the oil sector falls. Crisis-hit Chinese property giant Evergrande saw its shares jump when it resumed trading in Hong Kong, but its future is unclear. And the BBC&#8217;s Paul Kenyon tracks down one of the so-called &#8220;dark fleet&#8221; ships carrying Russian oil, despite G7 sanctions.</p>