Mexico City Case Study

Altitude

2200m

Mountains

Sierra Madre Occidental and Sierra Madre Oriental

Mountains Reaching 5000m

Sinking ground

Located on an old lake bed, sinking due to over extraction of groundwater from the aquifer.

Since the beginning of the 20th Century the city has sunk 9 metres in some areas

Seismic activity

Tectonically active area - volcanoes and earthquakes

Physical factors causes

• Temperature inversion

• Traps pollutants

• Subsidence issues

• Not physically ideal for a city

Population

22 million

Urban growth

• Natural increase

• Rural to urban migration

Rapid population growth

2 million - 1952

15 million - 1990

22 million - 2023

Human factors causes

Rapid population growth and rapid urbanisation has resulted in environmental, social and economic issues. Urban degradation

Domestic waste

As urban population increases, domestic waste increases

Development of economy → consumerisation → waste

Waste not disposed of properly in squatter settlements and unregulated industrial workshops

Industrial Waste

Industrial waste is waste generated by manufacturing or industrial processes - including: dust, gravel, masonry, concrete, scrap metals, oil, solvents, chemicals, wood, scrap lumber etc.

Can be hazardous - cleaning fluids, paints, chemicals, pesticides - can be released into water courses or left illegally on waste ground. They can infiltrate into ground and water - bad for water supply and soil health.

E-waste

This is discarded electrical waste.

Rise of ‘throw-away’ society and pace of technological innovation, consumers disposing of electronics every few years (outdated/ unfashionable)

Consumerisation

Health risk - unregulated - exported to developing countries

1980’s solid waste production

11000 tonnes of rubbish produced everyday

¾ formally removed

¼ remaining - dumped in open ground, waterways or left in streets

How many locations have been identified as unofficial solid waste dumps

21000 locations

ravines, sides of highways, vacant land

What do the unofficial waste sites encourage

Vermin in the areas

Risk to public health (disease)

Environmental degradation

How much carbon dioxide does burning solid waste produce?

242000 tonnes

Solutions to solid waste land pollution

• landfill

• incineration

• recycling

• reusing

• reduce

• composting

• biogas plants

• education

What is the big landfill site called?

Bordo Poniente Landfill

Bordo Poniente Landfill (story)

In 1985, Bordo Poniente became the sole sanitary landfill for Mexico City. As the population grew, the amount of solid waste increased.

In 2010, the city government decided to close it.

Bordo Poniente 25 years later - dimensions

370 hectares

17 m deep

70 million tonnes of rubbish

One of the world’s biggest rubbish sites

How much waste do 10 million inhabitants produce everyday in Mexico City?

13000 tonnes - 2/3 sent to landfill

BMLMX Power Company Biogas Plant (facts)

Treat 1.6 million tonnes of household waste per year

Produce 965 GWh of electricity per year

Each day, it will transform 1/3 of the city’s household waste to green energy

Barter Market

Launched by the Mexican Government’s environmental agency weeks after Bordo Poniente Landfill closed

Residents bring along recyclable waste that can be exchanged for vouchers to spend at nearby farmers markets

4000 people go

Exchange an average of 15 tonnes of waste every month

Barter Market Advantages

• Recycling more waste

• Raising awareness

• Buy fresh, locally grown food

• Good for health - reducing malnutrition

• Good for local farmers (economic)

• Generates public and private sector jobs

• Authorities say 128290 tonnes of recycled waste was collected in 2014

Air pollution causes

• Rapid growth of Mexico City

• City’s altitude

• Topography of the city

• Surrounding mountains - temperature inversions, preventing pollutants dispersing

• Vehicles add 12000 tonnes of pollutants

• Age of vehicles (no catalytic converter)

• Large number of commuters - live in east and industry in north and west

Air pollution consequences

• Health issues

• 1000 deaths per year

• 35000 hospitalisations per year

• ½ newborn children in Mexico City have levels of lead in their blood high enough to impair their physical and mental development

Hoy No Circula programme

Introduced in 1989

Bans cars from driving into the city on certain days according to vehicle registration numbers

Hoy No Circula Advantages

• Reduces congestion

• Reduces pollution

• Reduces cars on road

Hoy No Circula Disadvantages

• Rich can buy multiple cars and go in to the city centre

• Defeats the purpose of having less cars on the road and less pollution

Verificacion

Exhaust monitoring programme

A car’s pollutant emissions are analysed every 6 months

Via Verde

Multi-layered roads to reduce congestion

Second tier 15m (La Marquesa - Paseo Tollocan)

$115 million

Semi-effective:

• Reduced pollution from congestion

• BUT encouraged cars

Car Free Days

Every Sunday, the main finance area of the city is closed to all traffic, except bikes, pedestrianised the city

Only a small area of the city is closed to vehicles

Some of the city’s oldest and narrowest streets have been pedestrianised to make room for free flow of buses, bikes, pedestrians, and marketplaces

Car Free Days Advantages

• Reduce pollution

• Encourage exercise

• Good for businesses

• Improve air quality

Improving bus services

Provided funds to improve bus services

Bigger, more efficient articulated buses along 4 routes - speed commuting and reduce pollution

5% of Mexico City’s residents have swapped from private vehicles to public transport

Bus Services Disadvantages

Expensive

Needs more investment to fully improve public transport

Focus on one public transport to fully feel the benefits (Curitiba)

Metro Advantages

• Reduces car use in the city

• Cheap

• Quick (efficient)

• Clean

• Stations underground - more space for green space

Metro Disadvantages

• Expensive - $2 billion

• Needs to be maintained (expensive)

• Needs more investment - focus on one public transport system and investment goes further

• Expensive to extend and machinery

• In Summer the heat is debilitating and dangerous underground

Ecobici

Introduced in 2009, to reduce number of vehicles and air pollution

275 stations, 4000 bikes throughout the city

One person switching from driving to cycling for a 12 mile roundtrip saves 1.3 metric tonnes of CO2 a year

Encouraging exercise

Water pollution causes

Growing population - water supply and sewage treatment cannot cope

Dumping of waste

Grand Canal

Mexico City’s open sewage canal (raw sewage)

Used as fertilisers in the states of Mexico and Hidalgo

90% of hazardous waste is released into the Grand Canal and the water supple is being contaminated at the source

Serious health issues arising

Penuco River

The Penuco River receives 2000 tonnes of untreated waste each day

Much of this water flows to farming land north of the city to irrigate crops

HEALTH RISK - contamination of crops (high levels of lead)