Why a photocopy is not enough
According to the UK Foreign, Commonwealth & Development Office, you should "always carry your passport with you," since "police carry out random checks, especially during periods of heightened security," and a photocopy will not satisfy that check. The same advice notes that failing to present identification when asked "can bring fines or detention," which is a meaningfully different outcome from simply being asked to explain yourself. The advice is available in full on the UK government's China travel page, and it is worth reading before you travel rather than relying on a summary. Keep the passport itself in your bag or pocket for the day, not left at the hotel for safekeeping.
Where your passport is needed anyway
Beyond police checks, your passport comes up in several ordinary situations that have nothing to do with security. Hotels check guests in against the passport used to make the booking, and a mismatch can slow things down at the desk. Reservations at some attractions are made in your passport name and checked against it on entry, and rail tickets bought under your name are generally tied to the same document. A few payment or SIM registrations also ask for passport details at setup, so it is one document that follows you through most of a day's logistics rather than something you only need for a checkpoint.
Carrying it without losing it
The practical risk with carrying your passport daily is losing it, not being asked for it, so the carrying method matters more than the decision to carry it. A zipped inner pocket in a jacket or a bag with a closed zip works better than a back trouser pocket, especially on Chongqing's steep streets, stairways and cable cars, where a loose pocket is an easy way to drop something without noticing. Keep a separate photo of your passport's data page and any visa saved offline on your phone, so you have a reference even if the original goes missing for a few hours. Avoid keeping anything else valuable in the same pocket or pouch as the passport, since a single loss then only costs you one document rather than your cards and cash as well.
Photography and sensitive locations
The same UK advice notes that "all foreign nationals travelling to or around 'sensitive' areas might attract more attention from the authorities, including when taking photographs," and that unauthorised foreigners entering restricted military zones face "detention, fines or deportation." Chongqing is a large, modern city and most of it carries no special restriction, but government buildings, military installations and some infrastructure sites can fall into this category, and signage or a guard's gesture is usually the clearest signal. If a location feels like it might be sensitive, or a sign warns against photography, put the camera away rather than testing it.
Taxis and avoiding a dispute
Official advice is direct on this point: "avoid travelling in unmarked or unmetered taxis, as there have been incidents of sexual assault and robbery against foreign nationals." Use a marked, metered taxi from a proper rank, or book through a ride-hailing app instead of flagging down an unmarked car on the street. If a fare dispute does happen, the same advice warns against physical confrontation, since it "can lead to detention regardless of fault." Walking away from an argument over a fare, even one that feels unfair, is the lower-risk option every time.
If you lose your passport
Report a lost or stolen passport to the local police first, since you will generally need a police report to support anything that follows. From there, contact your embassy or consulate, which handles emergency travel documents for citizens in this situation, though the exact process and timeline depend on your nationality and consular resources in the region. Practically, expect it to affect any onward domestic travel booked in your name until a replacement or emergency document is issued, so build in some flexibility if this happens partway through a trip.
Before you head out for the day
Check your passport is on you, not in the hotel safe, before you leave for anything beyond a walk around the block. In a city built on steep streets and connected by cable cars and funiculars, a secure inner pocket does more work than remembering to bring the document in the first place.