(CNN) 2019 was the year of youth activism. Around the world, students and young adults took matters into their own hands, fighting for social issues like gender equality and climate action.

Some movements in Asia saw significant leaps forward, like the legalization of gay marriage in Taiwan. In other places like Hong Kong, now in its sixth month of pro-democracy protests, the struggle has no clear end in sight.

One theme connects these seemingly disparate issues across all countries. Young people are standing up and demanding change because it's their future at stake. They are the ones who will live to see the consequences of action taken now.

Here are five young leaders driving change in Asia.

The fight for marriage equality in Taiwan

Weng Yu Ching, 24, has been campaigning for LGBT rights in Taiwan since she was a teenager.

Weng Yu Ching, 24, remembers the moment Taiwan legalized gay marriage. She was in Taipei on a May afternoon, along with thousands of other LGBT activists draped in rainbow flags as they awaited the announcement.

When it finally came, the crowds erupted in cheers. People cried openly. Weng, too, was "very happy and very emotional."

"I felt very fulfilled," she said. "I felt like, wow, we did something really great."

It had been a long road to that point -- both for Weng, who works at non-profit organization Taiwan Marriage Equality Coalition, and for Taiwan, which is now the first and only place in Asia to legalize gay marriage.

People celebrate after Taiwan's Parliament voted to legalize same-sex marriage on May 17, 2019 in Taipei.

Weng has been fighting for LGBT rights since she was 17, when she saw a pride parade for the first time in her home city of Kaohsiung. Interest piqued, she made friends in the LGBT community and worked at an LGBT support hotline, chatting with closeted people who often "fear rejection due to their sexuality."

In 2017, Taiwan's courts ruled that the existing marriage laws were unconstitutional and ordered parliament to amend or enact new laws by 2019 -- sparking an acrimonious nationwide debate about LGBT rights.

Weng would spend hours at a time campaigning on the streets, trying to raise public support and awareness -- sometimes right next to anti-LGBT groups trying to do the same thing for their side.

After months of lobbying legislators, social media campaigns, and volunteer work, it felt "amazing" to see the same-sex marriage law finally pass, Weng said. For her, the best part came after the big announcement -- when she began receiving wedding invitations from same-sex couples, many of whom had waited years to legally tie the knot.

There's still work to be done, especially in rural areas where queer youth have less access to resources and support. But this year has been a victory -- and a sign that times are changing.

"People are accepting LGBT people more and more," she said. "We're the first in Asia. I'm very proud of my country."

A landslide election victory in Hong Kong

Jocelyn Chau was elected district councilor of Garden City, North Point, in Hong Kong in November 2019.

In 2019, Hong Kong erupted into chaos.

Pro-democracy, anti-government protests began in June and have not stopped since, with protesters demanding greater democracy and an investigation into alleged police brutality.

Young people have always been on the front lines, clashing with police -- but in November, they were also on the ballot.

Young pro-democracy candidates swept to victory in the local district council elections, which many framed as a de facto referendum on the protests.

Jocelyn Chau, 23, is one of the newly-elected councilors, representing the City Garden constituency of North Point, on Hong Kong Island. She was a teenager in 2014, when pro-democracy protesters occupied city streets for 79 days in the Umbrella Movement. She was still a student, so could only attend protests and marches, but it inspired her to consider political action.

"I was thinking, in what way can I help society in the future?" she said.

She worked as a client manager at a bank after graduation -- but then this summer's protests kicked off, against a China extradition bill pushed by the city's leader and government.

"I couldn't bear to see (the administration) put Hong Kong into jeopardy," she said. "So I decided to step forward and run for (the district council)."

Chau's platform wasn't explicitly political, instead focusing on community issues, but she still became a target in the city's hyper-charged tensions leading up to the elections. In October, she was attacked while campaigning on the street, punched by a man who tore up her posters and threw them to the ground.

She wasn't seriously injured, and posted a video of the attack to Facebook , where it has been viewed over 830,000 times. The online support also translated into an offline election victory, and in November she unseated the former councilor, who had held the seat for over 20 years.

Now, she hopes she can use her position to create dialogue with the residents in her constituency -- as well as safeguard Hong Kong's unique freedoms. She expressed concern for Hong Kong's independent judicial and legal system, reflecting a common fear among the movement that mainland China may be encroaching on the city's precious and limited autonomy.

"To protect the future of society, you must step forward," she said. "I hope democracy can be fully highlighted in the future of Hong Kong."

Choking on pollution in India

Climate activist Ridhima Pandey in New Delhi, India, on September 26, 2019.

Ridhima Pandey is only 12 years old, but her name and face have been broadcast worldwide.

She is one of 16 young activists -- including Greta Thunberg -- who jointly filed a complaint with the United Nations in September, accusing five of the world's leading economies of violating children's rights by inaction toward climate change.

Pandey, who lives in India's northern Uttarakhand state, grew up learning about the environment -- but everything changed in 2013, when devastating floods and landslides in the region left thousands dead.

Distressed and confused by why the flood had been so bad, she began researching the impact of climate change on natural disasters. The more she learned, the more frustrated she became at the Indian government for failing to take action. "I really wanted to do something," she said.

With her father's help, she filed a petition against the government when she was nine years old, arguing that it had failed to adequately address climate change. The case was dismissed -- so she escalated it to the Supreme Court, where it is still pending.

Pandey still attends school -- but she also campaigns across the country, speaks at different schools and conferences, and pickets her own school on Fridays as part of the worldwide "Fridays For Future" climate strike movement. Next year, she plans to launch an organization that raises youth climate awareness.

In particular, she focuses on pollution and deforestation, the worst issues plaguing India. Air pollution in the capital of New Delhi reached record high levels this year , forcing schools to close and flights to be diverted. Residents complain of burning eyes, headaches and coughing. It's gotten so bad that an oxygen bar selling "pure" oxygen has opened in Delhi.

Indian youth at a climate strike in New Delhi on September 20, 2019.

These persistent problems have painted a bleak image of the future in Pandey's mind. Her biggest fear is a world warped by climate change, where "we'll be going to museums to see the trees," and where everyone has to wear oxygen masks to go outside.

Sometimes it doesn't feel fair. She's only 12 -- it shouldn't be her duty to "make the older generation realize what they've done and what they should do." But it doesn't feel like adults have given her much choice.

"You haven't left a future for us," she said. "How can we focus on our dreams?"

#MeToo in South Korean schools

Jihye Yang, 22, is one of the leading young feminist activists in South Korea.

Schools in South Korea don't always feel like safe spaces for young girls, said 22-year-old Jihye Yang. Instead, they're often sites of discrimination and sexual harassment.

Yang is one of the leading youth feminist voices in South Korea, which was rocked this year by protests against a spate of illegal filming cases. Women have been recorded in their homes, on the streets, and even in toilets.

Just this March, police said about 1,600 people in motel rooms had been secretly filmed, and the footage live-streamed online for paying customers.

Tens of thousands of women have marched in protest under the slogan "My life is not your porn" -- and girls are taking action in schools, too.

Women protest against illegal spycam filming on August 4, 2018 in Seoul, South Korea.

Now co-representative of youth organization Teenager Feminist Network WeTee, Yang began her activism when she was 16, infuriated by how female students were treated in school. They were ordered to "act and dress modestly," and teachers would often call out specific students in class to "judge their appearances," she said. Male classmates would "judge" their bodies in group texts, and faced no repercussions when teachers found out.

When the global #MeToo movement arrived in South Korea , Yang brought it to schools, organizing protests and student feminist groups. Female students spoke out for the first time about the sexual abuse and discrimination they faced every day in the classroom.

She also pushed for government action -- but felt their response was lukewarm. Dissatisfied, she went straight to the United Nations this February, speaking before the Convention on the Rights of the Child on the movement and the discrimination it targeted.

Progress did eventually come; the Ministry of Education set up a gender equality team and the first official channel for student victims to report sexual abuse. It's not a perfect solution -- students weren't sent any information about how to use the channel -- but it's a start.

More importantly, the culture surrounding gender is beginning to shift. More young girls are beginning to call themselves feminists and push back against patriarchal or misogynistic attitudes, Yang said.

"Teenagers have been considered incompetent beings who need to be represented by other people's voices," she said -- but "already, a change is happening in the younger generation."

Free speech threatened in Myanmar

Ye Wai Phyo Aung is one of the cofounders of Athan, an advocacy organization in Myanmar.

Ye Wai Phyo Aung isn't afraid to be arrested -- it comes with the job of being an activist in Myanmar.

Phyo Aung, 24, is the co-founder of Athan, an advocacy organization for freedom of expression. He helped form the group in 2018 amid an ongoing crackdown on freedom of speech, which has seen hundreds arrested and sued in recent years.

"The whole situation of freedom of expression in Myanmar is in danger," he said. "Not only activists, human rights defenders, journalists are in danger, but also ordinary citizens, community leaders, and so on are at risk."

Phyo Aung began his political activism in college as a student union member. Several years later, he met fellow activist Maung Saungkha, who had just been released from prison.

Saungkha had been arrested under a controversial telecommunications law that regulates online speech, and which critics argue violates human rights. As of November, 257 people have been arrested or sued under the law, including 37 journalists, according to a report by Athan. Authorities also used the law to order an internet shutdown in the restive Rakhine state, home to the persecuted Rohingya minority.

Phyo Aung, Saungkha, and a third Athan co-founder took it upon themselves to document injustices. Phyo Aung tracked protests, arrest cases and lawsuits, and published reports on the deterioration of freedoms under the current administration. Athan then brought this research to the international community, contributing to the UN Human Rights Council's periodic reports

Phyo Aung also works to effect change on the ground, distributing educational material to teach young people about their freedoms.

with a long history of comedic social commentary. It can be risky to criticize the authorities. This April, several performers were arrested after satirizing the armed forces in a traditional Thangyat performance, a spoken-word style playwith a long history of comedic social commentary.

Their arrest was decried by human rights organizations and activists, who accused the government of stifling dissent. But Phyo Aung isn't deterred.

"I know that prison or jail or any kind of repression cannot change my beliefs," he said. "Human rights, democracy, freedom and peace are my dream ... so arresting an individual like me cannot change my dream."