Image source, PA Media Image caption, Mexico are facing England for a place in the World Cup quarter-finals
A shelter-in-place order has been issued at the Azteca Stadium because of severe weather before the last-16 World Cup tie between Mexico and England.
The match in Mexico City is set to kick off at 18:00 local time on Sunday (01:00 BST Monday).
There has been heavy rain in the city during the day and reports of lightning above the stadium.
The current advice for supporters and media inside the ground is to remain in their seats.
Fifa held talks with the English and Mexican football associations on Friday after proposing the match be moved to 19:00 BST on Sunday (12:00 local time) before a U-turn resulted in the kick-off time remaining unchanged.
The match is still currently set to start at the scheduled time, but any lightning strikes in the vicinity of the stadium close to kick-off would mean the start of the match being delayed.
The arrivals of both teams has been pushed back but it is not clear when the sides will be permitted to enter the stadium.
The game will be broadcast live on BBC TV, BBC iPlayer, BBC Radio 5 Live and the BBC Sport website and app.
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Published 5 June Big screens inside the Azteca alerted people that an electrical storm was approaching and to remain in their seats, though many sought cover from the rain.
Play cannot begin until 30 minutes have passed since lightning was last detected within an eight-mile radius of the stadium.
With regards to delays caused by severe weather, Fifa has no power to make its own rules - it must adhere to the advice of local authorities.
In the United States, recommendations of the National Oceanic and Atmospheric Administration (NOAA) are used.
The NOAA says if any lightning strike is detected within eight miles of a stadium the game has to be stopped. The rules are the same in Mexico.
When there is an increased risk of lightning strikes, the safety of players and supporters is given paramount importance.
All players must leave the pitch, and fans must seek shelter away from their seats.
A mandatory 30-minute countdown begins. Each time there is a lightning strike inside the distance, the countdown clock resets to 30 minutes.
If a full 30 minutes has elapsed, the supporters can go back to their seats and players will have a short warm-up.
Sources told BBC Sport on Saturday that world governing body Fifa had been set to reschedule the fixture, and confirm in a statement, but news of the proposal angered both English and Mexican officials.
The English Football Association (FA) requested time to review the weather forecast in more detail.
As talks went on, concerns over the impact on player preparation, fan travel and the logistics around moving the staging of such a huge game were discussed.
The proposed change was first reported by local media in Mexico.
Fifa maintained no decision had been made and - after pushback from both associations - it was decided to keep the tie at its original kick-off time.
Thunderstorms and shower clouds have been developing around Mexico City in the last few hours.
On social media there are reports of downpours affecting parts of the city, however it is difficult to verify if lightning has been occurring close to the football ground itself.
The showers are likely to continue to grow, threatening disruption.
All eyes on the horizon and fingers crossed the storms stay well away, but it's a close call. Any storms are likely to linger for hours.
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Sources: BBC Sport
