China is getting tough on waste. And the southern city of Shenzhen is leading the way. It has been pioneering various garbage sorting initiatives for years. The city now classifies waste into four categories – recyclable, kitchen, hazard and others, which is consistent with the new national garbage sorting standard.

The priority is kitchen waste due to its sheer quantity and the associated pollution risks. Shenzhen has vowed that kitchen waste should be sorted out throughout the city by the end of 2019. The city has assigned special supervisors to make sure residents dispose of it properly.

Yang Hua is one of them. Her main duty is to correct residents' misconception and misconduct of garbage sorting. "Many residents used to throw plastic bags into the kitchen waste bin. We are there to tell them these should be thrown into hazardous waste bins, otherwise they will affect the kitchen wastes' disposal," said Yang. "It takes time to make these as a habit. But residents are improving day by day."

There is also another challenge with kitchen waste disposal – it stinks. Shenzhen has a yearly average temperature of 22 degrees Celsius, meaning the food leftovers can't stay long in the garbage bin.

But in one district, they already have a special plan in place – that is turning kitchen waste into something useful for the communities – like fertilizers.

Urban Management Chief of Lianhua sub-district Yuan Qingfeng explained how it works. "We've streamlined the disposal chain for kitchen waste, everything from sorting and transport to recycling. All of these are done inside the residential district and within 24 hours," said Yuan. He added that the approach not only helps save on transport and human cost, but also motivates residents to sort their garbage.

It's not easy to change old habits. It requires devotion, patience and a forward-looking mentality.

While these elderly people might not be around to see the fruits of their efforts, the next generations certainly will. And it's hoped if they look and learn now, they will see garbage sorting as a common practice in the future.