Altitude, water and air in Mexico City

Mexico City is higher than Denver, most locals don't drink the tap water, and a bad ozone day can take your car off the road. None of it is a dealbreaker once you know the rules.

The short version

Altitude: Mexico City sits at about 2,240 m, or roughly 7,350 feet [1]. That's well above the Mile High City's 5,280 feet. Most people feel short of breath for a few days, then adapt.
Water: Water from the city system is considered potable, but quality varies by neighborhood, and tanks and pipes along the way matter. Most households drink bottled or filtered water [2].
Air: The city reports an "Índice AIRE Y SALUD" daily [3]. On bad ozone days, the Megalopolis Environmental Commission (CAMe) declares a contingencia and tells people to stay indoors in the afternoon [4].
Hoy No Circula: Most cars stay off the road one weekday a week, and more during a contingencia. Cars with foreign plates have extra limits [5].

Adjusting to the altitude

What to expect

At about 2,240 m (7,350 feet) [1], there's noticeably less oxygen in each breath than at sea level. The city's official tourism site lists the common symptoms as sudden shortness of breath, dizziness, headaches, fatigue and loss of appetite, sometimes worse at night [1]. It also notes that because the city is below 3,000 m (about 9,840 feet), symptoms tend to be milder, slower or absent, and that visitors rarely have real altitude trouble except when climbing the nearby mountains [1].

What Americans most often notice: you get winded on stairs, your first run feels like a bad day at the gym, and two margaritas hit like four.

How to adapt

Take it easy for the first few days. Rest if you feel tired or short of breath [1].
Drink plenty of water and go easy on alcohol and smoking [1]. Dehydration makes altitude effects worse.
Skip hard workouts at first, then build back up over a couple of weeks.
For headaches, the city's guidance mentions ibuprofen or paracetamol (acetaminophen, aka Tylenol) [1].
Call 311 (LOCATEL) for city information and help; the tourism site says to press 6 for English [1]. For an emergency, call 911.

If you have heart or lung disease, are pregnant or have a child with asthma, talk to your doctor before you move. Altitude and air pollution can both make those conditions harder to manage.

Tap water: potable on paper, bottled in practice

The water system is run by SACMEX (Sistema de Aguas de la Ciudad de México). Water coming out of the city network is considered potable, and SACMEX says it monitors it so it's safe to drink, which in theory means you could drink straight from the tap [2].

In reality, quality varies by alcaldía and colonia [2]. Researchers have pointed to iron and manganese in parts of Iztapalapa, and a UNAM study flagged arsenic, boron and lead in several wells [2]. Water also passes through building cisterns and rooftop tanks (tinacos) before it reaches your faucet, and those get dirty if nobody cleans them.

In April 2024, residents in parts of Benito Juárez, which includes Del Valle and Narvarte, reported contaminated water with a bad smell. SACMEX said after five days of monitoring that the water was back to normal [6]. It's a good reminder that problems can pop up anywhere.

What most households do

Option	How it works	Good for
Garrafón (20-liter jug, about 5 gallons)	Delivered to your door, set on a stand or pump	Drinking and cooking; the local default [2]
Under-sink or countertop filter	Installed by you or the landlord	Drinking, if maintained
Boiling	Rolling boil, then cool	Backup during outages
Tap water	Straight from the faucet	Showering, dishes, brushing teeth for most people

Before you sign a lease, ask when the cistern and tinaco were last cleaned and whether the building gets water every day. Some areas have scheduled cuts in the dry season.

Air quality and contingencias

The daily index

The city's air quality site publishes the Índice AIRE Y SALUD, with a category such as "buena" (good) and a risk level, covering ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, PM10 and PM2.5 [3]. There's also an official "Aire" app [4]. Check it the way you'd check the weather back home.

Ozone is the big one. It builds up on sunny afternoons, which is why the health advice below focuses on the hours after lunch.

When a contingencia is declared

The CAMe activates Phase I of the environmental contingency program when ozone climbs too high. In February 2026, for example, it activated Phase I after an hourly ozone peak of 155 ppb at a station in Coyoacán [4]. During a contingencia, CAMe recommends [4]:

avoiding outdoor activity and exercise between 1 p.m. and 7 p.m.
suspending outdoor sports and events in that window
not smoking, especially indoors
working from home where you can and shopping online

If you have kids, their school will usually move recess and PE indoors. Runners learn to go out early in the morning.

Hoy No Circula: when your car stays home

Hoy No Circula ("no driving today") limits which cars can drive based on the last digit of the plate, the color of the sticker (engomado) and the emissions hologram from the state verification test. On normal weekdays, restricted cars can't drive from 5 a.m. to 10 p.m. [7].

The normal weekday schedule

Day	Sticker color	Plate ending
Monday	Yellow	5 and 6 [7]
Tuesday	Pink	7 and 8 [7]
Wednesday	Red	3 and 4 [8]
Thursday	Green	1 and 2 [8]
Friday	Blue	9 and 0 [7]

Cars with holograms 1 and 2 follow this schedule, and some Saturdays are restricted too depending on the hologram and whether the plate ends in an odd or even number [7]. Cars with the 0 and 00 holograms are generally exempt on normal days.

Foreign and out-of-state plates

US-plated cars don't carry a Mexico City hologram, so they're treated strictly. Cars with plates from outside the central Mexico megalopolis can't drive on weekdays from 5 a.m. to 11 a.m., also have a weekly no-driving day, and are restricted on Saturdays from 5 a.m. to 10 p.m. [5]. Sundays are free unless there's a contingencia [5].

The free Pase Turístico exempts a foreign car for 3, 7 or 14 days. You apply online with the car's registration and, for a US car, your temporary import permit. It doesn't apply during a contingencia [5].

During a contingencia: Doble Hoy No Circula

During a Phase I ozone contingency, many more cars are pulled off the road. In February 2026, the "Doble Hoy No Circula" took all hologram 2 cars, half of hologram 1 cars by plate digit, and some 0 and 00 cars off the road from 5 a.m. to 10 p.m. Cars without a hologram, including those on a tourist import permit and out-of-state plates, were treated like hologram 2 cars [4]. Electric and hybrid cars, motorcycles and people with a disability permit were exempt [4].

Driving on your restricted day can get you a fine, so don't wing it. Our guide to bringing a US car explains why many Americans in Mexico City end up not driving at all.

Your first two weeks, step by step

Day 1: Order a garrafón and ask your landlord about the cistern.
Days 1 to 5: Go slow, hydrate and skip the hard workouts.
First week: Download the Aire app and check the daily index.
Before you drive: Check your car's Hoy No Circula day, or apply for a Pase Turístico.
Ask around: Our community group for Americans in Mexico can point you to water delivery services and clinics near you.

Altitude, water and air in Mexico City: what your body and your car need to know