A wave of exceptionally hot weather has blasted parts of South and Southeast Asia this week
The clay-court tournament, originally set for May, has been rescheduled for September 12-20.
"The organisers... Expressed their doubts about being able to hold the tournament without health complications which could affect players, the public and staff," the Madrid Open organisers said in a statement.
"The organisers are analysing and evaluating in detail all the possible options, always thinking about guaranteeing the safety of all the members of the tournament."
Recent Covid-19 outbreaks in Madrid have left the tournament in serious doubt despite daily cases of the virus having previously fallen dramatically in Spain.
There have been over 2,000 positive cases a day in the country over the past week.
In total, Spain has recorded more than 288,000 cases of coronavirus since the start of the pandemic, and 28,445 deaths, according to the latest figures on Friday.
The Madrid Open was expected to see a stellar field, with world number two and five-time champion Rafael Nadal already confirming his participation.
The tournament is slated to start on the same day as the US Open women's singles final in New York and the day before the men's final.
A wave of exceptionally hot weather has blasted parts of South and Southeast Asia this week
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