“Under the new definition, a cheaper generic drug made in India can be imported and sold in China,” Dr. Huang wrote. “Given that these drugs are usually much cheaper than the prohibitively priced Western patented drugs, a significantly larger percentage of Chinese people can now afford those lifesaving drugs.”

According to Dr. Huang, the Indian version of the lung-cancer drug Iressa cost $10 a day in 2016, compared with $100 a day for the patented drug in China. He said generic drugs cost, on average, 97 percent less than patented drugs sold in China.

The lack of access to drugs has taken on more urgency as the Chinese government grapples with the mounting health problems of its 1.4 billion people. Heart disease, strokes, diabetes and chronic lung disease account for 80 percent of deaths in China, according to a World Bank report in 2011.

Cancer diagnoses in China are soaring, and survival rates are low. About 4.3 million cancer cases were diagnosed in 2015, or almost 12,000 a day. That was nearly double the rate five years before, according to official figures.

In China, the public has long expressed frustration with its lack of access to effective drugs to treat those kinds of diseases. A 2018 film, “Dying to Survive,” was based on the real-life story of a Chinese leukemia patient who smuggled generic drugs from India to save himself and others. A box office hit, it was almost universally lauded for shedding light on the difficulties of getting cancer drugs in China. The movie’s popularity prompted Premier Li Keqiang to call for speeding up price cuts for the medication.

Even the rich in China contend that red tape and stringent regulatory rules prevent them from getting access to new drugs that are approved in the United States, and many say they are forced to fly overseas for treatment.

Yuan Jie, a senior official with the Standing Committee of the National People’s Congress, a top group of Chinese lawmakers, said the decision to redefine the scope of counterfeit drugs was “a response to the concerns of the people,” according to an official transcript.