efe-epaBy Raúl Casado Madrid

Some of the world's cities with the dirtiest air, including Asian megalopolises such as New Delhi or Beijing, are represented at the COP25 climate summit currently underway in the Spanish capital, where officials were able to experience on Wednesday a simulation of the health risks posed by breathing in polluted air.

Data by the World Health Organization shows that bad air quality causes 7 million premature deaths per year across the planet and often worsens many pre-existing conditions, resulting in skyrocketing healthcare costs.