Revolutionizing Fruit Preservation: Dr. Nguyen Van Kai and his Ozonic Liquid

Nguyen Van Kai, known as Mr. Ozonic Liquid, is a chemist famous for his preserving fluid that extends the lifespan of fruits and vegetables. Produced in Hanoi, the liquid is claimed to kill bacteria and pests safely. Despite its benefits, Kai faces challenges convincing farmers of its safety. The liquid's patent was acquired from Russian scientists, and Kai is the sole promoter in Southeast Asia. In Langson province, agriculture thrives, particularly custard apples, but farmers face difficulties in harvesting. Kai demonstrates his product to local farmers, aiming to improve their produce preservation.

Describe the process of harvesting custard apples as mentioned in the text.

What is the significance of the location where Dr. Nguyen Van Kai demonstrates his Ozonic liquid?