Firstly prepare the vegetables to be pickled. Peel and wash the carrots. Cut them lengthwise in half then chop them in 1cm pieces.
For the celery remove the leaves but do not throw them away. You can easily wash them, let them dry and then chop them up finely to store in the freezer. They are a great addition to stews.
For the pikla though use ONLY the stalks. The exterior celery stalks are a lot harder than the inner stalks, hence use a peeler to peel it off a bit. Cut the celery in 1cm pieces and the wider ends of the stalk cut in half also, so that they are all similar in size.
Place all the vegetables in a large enough bowl and then add enough vinegar to cover the vegetables completely. I required 2L of vinegar, you may need more or less depending on how many vegetables you cut up. Allow the vegetables to soak in the vinegar for a day or at least 12 hours.
Use a cup to measure the vinegar remaining and pour it in a large pot. Bring the vinegar and salt to a boil then reduce the heat to a medium/low. Mix in the flour and mustard. The amount of cups of vinegar that was added in the pot will determine the amount of flour and mustard you will add.
When we made it there were 9 cups of vinegar remaining after the vegetables were soaking in it, so we added 9 tbs of flour and 9 tsp of mustard powder. If for example you had 6 cups of vinegar remaining you would add 6 tbs of flour and 6 tsp of mustard powder. At this stage if you prefer the pikla to have a thicker consistency then add heaped tablespoons of flour.
Mix in the curry powder followed by the vegetables. The amount of curry you add may vary based on your tolerance levels. Stir everything together and allow the mixture to softly boil before taking it off the heat.
Spoon the pikla in the prepared jars, let it cool down, seal the jars and place them in the fridge for storage. I can't give you a shelf life exactly as they seem to be well maintained in the fridge and they don't last too long before they are consumed anyway.
With the ingredients used above, 3.6kg of pikla were made in the end.