The Department of Magical Accidents and Catastrophes is working overtime to correct this egregious magical error that seems to have befallen the region.
In the meantime, please do not panic. The darkness itself has been caused by a landscaping spell gone awry and the correct personnel for the job are working tirelessly to contain the magic, return Diagon to normal, as well as ensure such a thing does not happen again. Those responsible will be disciplined and fined appropriately.
Please try your best to go on with life as normal. The darkness itself is not damaging or dangerous in any way that can be identified.
Thank you.
[Mandy]I suddenly see a lot of overtime in my future after this.