中を details
Examples
amid — a formal preamble acknowledging a state (busyness, bad weather, inconvenience) the main clause proceeds within or despite
本日はお忙しい中をご出席いただき、誠にありがとうございます。
honjitsu wa o isogashii naka o go shusseki itadaki, makoto ni arigatou gozaimasu.
Thank you very much for attending today despite your busy schedule. formal
雨の降る中を、傘も差さずに歩いて帰った。
ame no furu naka o, kasa mo sasazu ni aruite kaetta.
I walked all the way home through the pouring rain without even an umbrella. neutral
Formation
（状態）＋中を（お忙しい中を・雨の降る中を）attaches to noun phrase (schematic)
Notes
The state comes in three shapes: i-adjective plain form (忙しい中を),
verb continuous (降る中を), or noun＋の (嵐の中を). を wants a
motion-ish main predicate (歩いて帰った); bare 中 has no such constraint.
verb continuous (降る中を), or noun＋の (嵐の中を). を wants a
motion-ish main predicate (歩いて帰った); bare 中 has no such constraint.
Related patterns
Similar
Both frame ongoing circumstance with 中, but 最中に pins the exact MOMENT an event interrupts (電話中に来客があった), while 中を politely names a state the listener is enduring or imposed upon (お忙しい中をありがとうございます) rather than a single interrupted instant.