India, Sept. 19 -- India's water crisis isn't going away anytime soon, and that's turning into real business for companies that specialise in treating, recycling and reusing water and industrial waste. As factories face stricter pollution norms and cities push for better waste management, a small set of niche players are seeing their order books swell. Two such companies just reported some of their strongest years yet, and the contrast between how they're funding that growth is worth digging into.

Apex Ecotech Limited shares hit upper circuit and closed at Rs. 262.5, up Rs. 12.5 or 5% from the previous close Rs. 250, with a market cap of Rs. 346 crore and a P/E of 19.36.

Felix Industries Limited shares closed at Rs. 206.15, up Rs. 2.20...