MADRID, Oct. 24 (Xinhua) -- The Madrid City Hall on Tuesday reactivated its anti-air pollution protocol and advised it would step up to level two of the protocol and its subsequent restrictions on traffic after levels of over 180 micrograms of nitrogen dioxide per cubic meter were measured in two monitoring stations in the Spanish capital.
It is the fifth time the protocol has been activated in under a month, coming just a week after it was de-activated.
Although Madrid experienced rainfall for the first time in 50 days on Oct. 17, warm and dry weather returned quickly to Madrid and temperatures around ten degrees centigrade above the average for the time of year and an almost total absence of wind has seen a steady buildup of nitrogen dioxide over the past five days.
The Madrid Town Hall website advises that the first stage of the protocol means that traffic on the M-30 ring road and on access roads into the capital is "limited to 70 kilometers an hour," both in an out of the city while recommending the use of public transport.
Meanwhile the second stage, which comes into effect on Wednesday, prohibits private vehicles of non-residents from parking in the city center.
A third level would limit the use of private vehicles on certain days of the week, with cars whose licenses end in odd numbers allowed to circulate one day and those with even numbers the next, effectively halving the number of cars on the roads.
With the current weather system expected to remain in place until at least the end of the week and perhaps, longer, it is possible level three could come into use in the coming days.
At the start of October, the Madrid Town Hall confirmed that as of December this year the central Gran Via would be closed to traffic on a permanent basis with only local residents, taxis and public transport able to use the main thoroughfare.