Mexico City - Mexico is facing an extremely heavy season of brush and forest fires, with 4,425 blazes recorded so far this year.

The Federal Environment Department said Wednesday that 3,800 firefighters are combatting an average of about 100 fires per day in brush, scrub, agricultural and forest land throughout the country. To date, about 378,000 acres (152,952 hectares) have been affected nationwide.

About 200 fires have directly affected Mexico City and its outskirts, and that doesn't include fires happening in other states.

Authorities declared an environmental emergency on Tuesday for metropolitan Mexico City, as smoke from nearby wildfires pushed pollution to levels deemed potentially harmful to human health.

Environmental authorities advised CDMX residents to avoid outdoor activities and exercise and remain indoors with windows and doors shut. It called for especially sensitive groups, including infants, the elderly and sick, to stay at home.

For much of Mexico, fire risk is highest in the spring months because the summer rainy season has not yet started.

Authorities declared emergencies in 11 municipalities in the Southern State of Oaxaca due to raging forest fires on Sunday, and in the Pacific State of Jalisco, more than 300 firefighters attempted to stamp out five blazes outside Guadalajara on Saturday.