As a Brahmin i get to perform and be part of Havans almost every month. Does that make me lucky? No. There is no spiritual or practical use of havans. Hence we Hindus shifted to the puranic culture, which patronises pooja over havan. Havans are elaborate and expensive. Its not that we are western but because expenses are sky high that havans are not a custom lately. Many of us dont have our own houses. Expecting our house owners to bear our havan is a little too much. A lot of carbon dioxide and water vapour is emitted through havans which will only add, only in trace amounts though, to the green house effect. Havans make it difficult for people with Asthma and other respiratory troubles. They irritate eyes and smoke your clothes.
Seeing no possible benefits in practical way one might say that yagnas are what gods require. Yes they did. But in Vedic times. Back then we were heavily reliant on cattle and every Brahmin household had many cows, making it easy to procure items of yagnas. Hindus today won't even recognise the Vedic gods who we worshipped 2000 years before Christ was born. Our spirituality and its meaning has changed with our customs over years. Havans are only for specific functions now. They are neither our primary method of worship nor a habit of good health.
The stronger a light shines the darker are the shadows around it.