Working in the entertainment industry, I've always been  told that when you look good, you feel good...but is that really the case? Personally, I have had days where I've gone though hair, make-up and a visit to the wardrobe department where I come out looking glam but still feel like something isn't right. When I'm on a job, I don't always have a choice in the matter of what I wear or how I look because that's just the nature of the television business. However, when I'm not on screen or at a shoot – that's when I truly feel like myself because I can wear whatever I want – my favorite pair of distressed jeans, my super soft purple tee, a cozy boyfriend sweater...I can choose for myself.

Last July while working at Greenpeace International in Amsterdam, I took part in launching the Detox campaign by participating in the world's largest simultaneous striptease to challenge some of the biggest clothing brands in the world to create fashion without toxic pollution. As a member of the Chinese community, an environmental activist, and a public figure it was disheartening to find out that some of my previous fashion choices have contributed to the poisoning of rivers and other waterways in China as well as countries like Mexico where many big brands outsource their production.

But with knowledge comes power – the power of choice.

Zara is one of my favourite brands, they are always on trend but they also have unique pieces to mix and match so that I can create my own styles. In Greenpeace's latest investigatory report, "Toxic Threads – The Big Fashion Stitch-Up", Zara was singled out for having clothes that can give rise to chemicals that are both hormone-disrupting and cancer-causing – wait a minute, WHAT? Let's take a second and think about it – this major brand produces 850 million clothing items each year, resulting in the release of huge amounts of toxic chemicals into our water systems when these clothes are made and washed...the contamination of the most valuable and vital resource on our planet, water.

All for what? Disposable, fast fashion.

Less than a week after Greenpeace's public announcement targeting Zara to change their toxic ways, the clothing brand committed to detoxing their clothing operations by 2020. The reality is, there are more sustainable and affordable fashion alternatives out there.

If major international brands like Puma, Nike, Adidas, H&M, Marks & Spencer and now Zara can commit to progressive change, why can't Calvin Klein, Levi's, Mango and other big players do the same? Instead of continuing on this vicious cycle of placing profit over people and the planet, let's challenge them and give them a chance at becoming real industry leaders by helping transform the fashion and textile industry.

I am calling on all my fashion-forward, environmentally-conscious and trend-setting activists to join me in telling big brands like Levi's to follow the detox trend of its competitors and eliminate releases of hazardous chemicals into the environment and products by replacing them with safer alternatives. Show us that they are for real by being transparent and disclosing what each of their suppliers are releasing into our precious waterways. We want fast fashion, yes we do – as in the establishment of short timelines for achieving zero discharge of toxic chemicals throughout their supply chains ASAP.

When I feel good, I look good – I'd feel and look even better knowing that my clothing choices are helping to shape the future of fashion – one that is sustainable and pollution-free, how about you?

Hilary Tam is a Greenpeace activist, television presenter, Miss Chinese Toronto 2010 and former Miss Chinese International and Miss Hong Kong contestant.