Why did England manage to crush China quite easily in the first “opium” war?

Why did England manage to crush China quite easily in the first “opium” war? What are the reasons and which, in your opinion, is the main one?

The main reason for China’s defeat in this war was a significant gap in their development. China was an agrarian state where technology was poorly developed. At the same time, the British Empire was a powerful industrial state. She used the latest technological innovations in her army. This allowed her to achieve a huge advantage over the almost medieval Chinese armies.