Kuala Lumpur, Malaysia - "It's still so painful, it's like it happened yesterday," said Grace Nathan, whose mother Anne Daisy was on Malaysia Airlines flight MH370 that disappeared on March 8, 2014.

The plane, carrying 239 people, was on its way to Beijing from Kuala Lumpur.

Air crash investigators said the plane crashed in the Indian Ocean, a fair distance from its planned route.

Although parts of the plane have washed up on the shores of the Indian Ocean islands and the coastline of East Africa, the wreckage still has not been found.

A few days before the fourth anniversary of the aircraft's disappearance, Voice 370, a support group for MH370 next-of-kin, held a remembrance event at a shopping mall in suburban Kuala Lumpur.

Family members lit candles and observed a moment of silence. They paid tribute to the loved ones they lost, recalling their fondest memories and qualities.

The turnout was modest and Grace admitted that, over the years, families' involvement in such events has thinned.

I asked her if she feels that the world has moved on.

"I'm sure people have. A lot more people are wondering why we're still pursuing this," said Grace.

"I don't hold it against them because I know there have been many times in my life that I've been ignorant to someone else's tragedy or pain."

But the motivation for her and other families to ensure the search for MH370 continues stems not just from a desire to know what happened, but to ensure such a tragedy never happens again.

KS Narendran's wife, Chandrika, was on the plane. The Chennai-based management consultant travelled to Kuala Lumpur to take part in the remembrance event.

"It's important to know what happened. If it's happened once, it can happen again," he said. "There's a bigger question of safety in aviation that needs to be addressed."

Since the incident, the International Civil Aviation Organization has moved to improve flight safety standards. Starting in November this year, planes flying over open oceans will have to report their position every 15 minutes instead of 30.

By July 2018, flight data recorders, which are useful in determining what happened in aviation disasters, will have to be equipped with underwater locator beacons that can last at least 90 days, instead of the current 30 days.

"These are all good, positive developments that have come about from a lot of the noise that we have made," said Grace.

The search for the missing plane is now carried out by Ocean Infinity, a private exploration firm based in Texas under a "no find, no fee" agreement with the Malaysian government.

Ocean Infinity will be paid if it locates the wreckage within 90 search days, a deal that was struck a year after the Malaysian, Australian and Chinese governments suspended the search in 2017.

The search started on January 22 but is expected to continue until June, because the vessel has to return to shore to refuel, and bad weather may hamper operations.

Malaysia's civil aviation chief, Azharuddin Abdul Rahman, told reporters at the remembrance event that "for the aviation world, we want to know what exactly happened to the plane".

So too do the families of those on board.

"We have to remain optimistic. I don't know if we have an alternative," said Narendran.

For Grace, the possibility that the plane will not be found is not a thought she wants to entertain.

"I understand if this fails, it's going to be really, really hard to convince anyone to start a search again."