Step 1: Understanding the Concept:
FSSAI regulations define standards for alcoholic beverages based on residual sugar, alcohol strength, and titratable acidity.
Step 2: Detailed Explanation:
In dry wine, yeast converts virtually all fermentable hexose sugars into ethanol and carbon dioxide during vinification.
Under regulatory standards, dry wine is classified as containing residual sugar levels of $0.4\text{--}0.9\,\text{g}/100\,\text{mL}$ (or up to $0.9\%$).
Semi-dry wines contain $1.0\text{--}3.0\%$, while sweet dessert wines exceed $4.5\%$.
Step 3: Final Answer:
Therefore, the sugar content in dry wine as per FSSAI regulations is 0.4 - 0.9.