The Taj Mahal in Agra is one of the most beautiful monuments on the earth. It was built by the Mughal ruler Shah Jahan in memory of his deceased wife Mumtaz Mahal. It is built entirely of white marble and was declared as a UNESCO world heritage site in 1983. It attracts scores of tourists from all over the world. But now the monument has developed a yellowish tinge (and in some areas ugly brown and black spots) owing to the increased levels of pollution around the area. The main pollutant is Sulphur dioxide released by the industries which later reacted with rainwater decreases the pH level of rainwater. Suspended particulate matter (SPM) was also one of the culprits. Thus, M. C Mehta, an attorney in the supreme court of India and an active environmentalist, filed a writ petition in 1984 mentioning the adverse effects of the industries and vehicles in the area on the Taj Mahal. He sought appropriate directions to be given to the concerned authorities to take immediate steps to stop air pollution in the area and save the Taj. This petition falls under Public Interest Litigation (PIL). a. Explain the effects of the phenomenon mentioned above. b. What are the safety measures to be taken to the control the above-mentioned phenomenon?

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

pre-sliced bread is a relatively recent development in baking technology. previous to that, it was always sold in a bakery in daily-made contiguous loaves with no wrapping, and was moderately perishable, usually being used with a day or two (which is why every bakery had a discounted “day-old” bread table.) therefore, pre-sliced bread would grow stale quickly. the hard crust provided a protective layer, and once the exposed dry slice left from the previous cut was removed, the interior was still soft.

what keeps bread soft is the moisture retained in the crumb (the light spongy part that’s not crust). the reason the crust develops is the surface of the dough gets exposed to hot dry air during baking which browns the outer layer and seals it, preventing all the moisture from escaping the dough. longer exposure to air will also eventually cause your bread to lose flavor and become stale.

people were used to cutting slices as they needed them and storing bread in a specially-made wooden or metal breadbox or pail with a lid to preserve it longer, but the first automatically sliced commercial loaves were produced on july 6, 1928, in chillicothe, missouri, using a machine invented by otto rohwedder, an iowa-born, missouri-based jeweler.[1] pre-sliced bread would indeed dry out, were it not for another 20th century technology: the plastic bag. bread could now be pre-sliced, and if the enclosing bag remains sealed as much as possible, the bread will remain soft and fresh for longer than if sitting unwrapped on a shelf or enclosed in a bread box that is not air-tight. sealed packaging meant bread could also be sold on store shelves and eliminate frequent trips to a bakery.

sealing bread in a plastic bag had another effect: the moisture in the loaf will re-distribute into the crust and soften it, which is sometimes more pleasing in a sandwich - especially for children whose teeth might not yet be strong enough to tear through a hard crust. a homemade loaf of bread can be sealed in a bag overnight and the crust will become soft like store-bought sandwich bread.

these were novel changes in how bread was produced and sold, which led to the coining of the phrase “the greatest thing since sliced bread.”