As climate change makes smog and bushfires more common, people will die from air pollution at increasingly high rates – especially in densely populated cities.
Rising costs of living and airfares point to long-haul travel being affordable for fewer people. It also might re-shape the way we think about tourism.
Transport is one of the world's biggest polluters, but on the path to net zero, aviation is reinventing itself, potentially building a new kind of jet age.
Malaysia seeks to ensure that the poor benefit from fuel subsidies instead of the rich, but rationalisation can also contribute towards sustainability. Savings from removing fuel subsidies can be used to develop low-carbon alternatives.