Twenty years ago, I drove a cab for a living. Once I arrived in the middle of the night for a pick-up at an old building. I walked to the door and knocked.

“Just a minute,” answered a weak and elderly voice.

After a long pause, the door opened. A small woman in her 80’s stood in front of me. By her side was a small nylon suitcase. The apartment looked as if no one had lived in it for years. I helped her take the suitcase to the cab. She kept thanking me for my kindness.

When we got in the cab, she gave me an address, then asked, “Could you drive through downtown?”

“It’s not the shortest way,” I answered.

“Oh, I don’t mind,” she said. “I’m in no hurry. I’m on my way to a hospice（收容所）. ”

“I don’t have any family left,” she continued “The doctor says I don’t have very long. This would be the last time for me to go downtown.”

I quietly reached over and shut off the meter. For the next few hours, we drove through the city. She showed me the building where she had once worked. We drove through the neighborhood where she and her husband had lived. When the sun rose, she suddenly said, “I’m tired. Let’s go now.”

We drove in silence to the address she had given me. Then we arrived at a low building. Two orderlies came out to the cab.

“How much do I owe you?” she asked.

“Nothing,” I said.

Almost without thinking, I bent and gave her a hug. She held onto me tightly.

“You gave an old woman a little moment of joy,” she said. “Thank you.”

I squeezed her hand, then walked into the dim morning light. On a quick review, I don’t think that I have done anything more important in my life.

Beijing, together with many regions in northern China, experienced a sandstorm on Monday. The sandstorm is the strongest and the most sweeping one in nearly a decade, according to the National Meteorological Center.

Starting from Monday to Tuesday, affected by cold fronts and heavy winds, floating sand and dust were expected to sweep parts of Xinjiang, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Gansu, Ningxia, Shaanxi, Shanxi, Hebei, Beijing and Tianjin, forecast the center. The center has advised the public to take precautions against the heavy winds and sandstorms, and suggested that drivers prepare for poor visibility. The center also predicted that it would not end soon.

Remote sensing images of dust in northern China show the dust from southern Mongolia gradually traveled south with the airflow.

Visibility remained low in Beijing as the municipal observatory issued a yellow alert. The yellow alert, or the second-lowest level in the four-tier weather alert system, was issued at 7:35 am by the Beijing Meteorological Service on Monday. It said the sandstorm would continue during the day time and the visibility would be lower than l,000 meters at noon.

At 9 am Monday, the city’s level of PM10 particles reached 8,108 micrograms per cubic meter at six major urban districts, with the city seeing heavy pollution.

The Beijing Capital International Airport canceled 247 flights and the Beijing Daxing International Airport 181 flights by 9:30 am Monday due to the sandstorm. The total planned inbound and outbound flights in the capital airport for today was 1,141, which means more than 20 percent of the flights have been canceled. For the Daxing airport, the total number of planned inbound and outbound flights for today was 846 and 21.39 percent of them have been canceled.