More than one fifth of the population of Mexico on looking towards the Popocatepetl volcano as schools and farmers begin preparing for an eruption.

The volcano, also known as "El Popo", has been continuously spewing gas and volcanic ash into the sky for a number of weeks and is currently on step five of a seven-level warning scale.

More than one fifth of the 114 million population of Mexico live within a 60 km (37 miles) of the volcano.

In the surrounding areas of Puebla and Morelos schools have already been temporarily closed as a precaution. Now re-opened, they have begun their preparations for an evacuation in case the 5,450-meter volcano does erupt.

Even if a majority of those people will not be affected by any lava that may spew from the core, the volcanic ash and dust that has continuously been thrown into the air could damage people's health for miles around.

Local school principal David Leyva Gonzalez warned against complacency. "They (students) don't take it very seriously. They have seen it and they want to go out and play but it's prohibited to play sports or something that may affect breathing but they don't see it like this. They are influenced by the community that nothing is going to happen," he told Reuters.

The ash and gas look could potential damage crops around the area, causing a concern for local farmers.

Mexico's National Centre for Disaster Prevention said the warning could stay in place for weeks to come.