That noise is produced by cheap Chinese electronics, they don't install filters to make it more cheap, so it flood environment with a high RF noise up to 4-5 MHz. Probably someone of your neighbors bought some cheap chinese device and when it is powered you're got that noise hell.
But that noise floods mostly building, if you get your receiver and move 50-100 meters away from building and mains lines, you can listen a lot of MW stations with a nice quality.
That noise affects not only MW, but also SW, FM broadcast and VHF bands. When mains outage happens for entire city, it's easy to listen FM and VHF stations from neighbor cities which is about 100-150 km away, because noise floor drops down very significantly and you can listen very weak stations as a clean signal.
If you want to listen MW band, there is needs for external antenna placed as far as possible away from any buildings and mains lines. Also coax cable for such antenna needs to use ferrite RF chokes to block common mode RF noise which is received on outer side of the coax cable shield.