You're asking if over 600mm of rain (i.e. more than half a year's worth) in a 24...

You're asking if over 600mm of rain (i.e. more than half a year's worth) in a 24 hour period in Henan was caused by recent installments of agricultural field drainage? Or if that caused the jet stream to hold the storm over NRW to drop months worth in a 24 hour period?

1. https://weatherspark.com/y/127378/Average-Weather-in-Zhengzh...

2. https://weatherspark.com/y/58162/Average-Weather-in-Wupperta...