No, curry powders should not be stored in transparent containers. Exposure to light degrades the quality and flavor of the spices.
Curry powder is a blend of many different spices, each with its own unique flavor profile and volatile oils. These oils are what give curry powder its characteristic aroma and taste. Light, especially sunlight, can cause these oils to break down and evaporate, leading to a loss of flavor and potency. Transparent containers allow light to penetrate, accelerating this degradation process. Opaque containers, on the other hand, block light and help to preserve the quality of the curry powder for a longer period. Ideally, store curry powder in an airtight, opaque container in a cool, dark place like a pantry or cupboard. This will help to maintain its flavor and aroma for as long as possible.
To further extend the shelf life of your curry powder, consider storing it in the refrigerator, especially if you live in a warm climate. Just be sure the container is airtight to prevent moisture from getting in and clumping the powder.